161906725 has 12 divisors (see below), whose sum is σ = 212574564. Its totient is φ = 121905920.

The previous prime is 161906711. The next prime is 161906761. The reversal of 161906725 is 527609161.

It can be written as a sum of positive squares in 6 ways, for example, as 10099684 + 151807041 = 3178^2 + 12321^2 .

It is not a de Polignac number, because 161906725 - 2⁷ = 161906597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 190054 + ... + 190903.

It is an arithmetic number, because the mean of its divisors is an integer number (17714547).

Almost surely, 2^161906725 is an apocalyptic number.

It is an amenable number.

161906725 is a deficient number, since it is larger than the sum of its proper divisors (50667839).

161906725 is a wasteful number, since it uses less digits than its factorization.

161906725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380984 (or 380979 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 161906725 is about 12724.2573457157. The cubic root of 161906725 is about 545.0315331192.

The spelling of 161906725 in words is "one hundred sixty-one million, nine hundred six thousand, seven hundred twenty-five".