161978725 has 6 divisors (see below), whose sum is σ = 200853650. Its totient is φ = 129582960.

The previous prime is 161978723. The next prime is 161978767. The reversal of 161978725 is 527879161.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 332929 + 161645796 = 577^2 + 12714^2 .

It is not a de Polignac number, because 161978725 - 2¹ = 161978723 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161978723) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3239550 + ... + 3239599.

Almost surely, 2^161978725 is an apocalyptic number.

It is an amenable number.

161978725 is a deficient number, since it is larger than the sum of its proper divisors (38874925).

161978725 is an equidigital number, since it uses as much as digits as its factorization.

161978725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6479159 (or 6479154 counting only the distinct ones).

The product of its digits is 211680, while the sum is 46.

The square root of 161978725 is about 12727.0862729849. The cubic root of 161978725 is about 545.1123130761.

The spelling of 161978725 in words is "one hundred sixty-one million, nine hundred seventy-eight thousand, seven hundred twenty-five".