161938222995025 has 81 divisors (see below), whose sum is σ = 205543608169107. Its totient is φ = 126562683072000.

The previous prime is 161938222995011. The next prime is 161938222995083. The reversal of 161938222995025 is 520599222839161.

The square root of 161938222995025 is 12725495.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 113703642302481 + 48234580692544 = 10663191^2 + 6945112^2 .

It is not a de Polignac number, because 161938222995025 - 2⁴¹ = 159739199739473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 726180372064 + ... + 726180372286.

Almost surely, 2^{161938222995025} is an apocalyptic number.

161938222995025 is the 12725495-th square number.

161938222995025 is the 6362748-th centered octagonal number.

It is an amenable number.

161938222995025 is a deficient number, since it is larger than the sum of its proper divisors (43605385174082).

161938222995025 is an frugal number, since it uses more digits than its factorization.

161938222995025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 884 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 41990400, while the sum is 64.

The spelling of 161938222995025 in words is "one hundred sixty-one trillion, nine hundred thirty-eight billion, two hundred twenty-two million, nine hundred ninety-five thousand, twenty-five".