The totient function \$\phi(n)\$, also called Euler's totient function, is defined as the number of positive integers \$\le n\$ that are relatively prime to (i.e., do not contain any factor in common with) \$n\$, where \$1\$ is counted as being relatively prime to all numbers. (from WolframMathworld)
Given an integer \$N > 1\$, output the lowest integer \$M > N\$, where \$\phi(N) = \phi(M)\$. If \$M\$ does not exist, output a non-ambiguous non-positive-integer value to indicate that M does not exist (e.g. 0, -1, some string).
Note that \$\phi(n) \geq \sqrt n\$ for all \$n > 6\$
Where M exists 15 -> 16 (8) 61 -> 77 (60) 465 -> 482 (240) 945 -> 962 (432) No M exists 12 (4) 42 (12) 62 (30)
Standard loopholes apply, shortest answer in bytes wins.