161921158725 has 48 divisors (see below), whose sum is σ = 272574349760. Its totient is φ = 84793651200.

The previous prime is 161921158703. The next prime is 161921158727. The reversal of 161921158725 is 527851129161.

It is not a de Polignac number, because 161921158725 - 2¹⁰ = 161921157701 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161921158727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2609106 + ... + 2670444.

Almost surely, 2^161921158725 is an apocalyptic number.

161921158725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161921158725 is a deficient number, since it is larger than the sum of its proper divisors (110653191035).

161921158725 is a wasteful number, since it uses less digits than its factorization.

161921158725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61990 (or 61985 counting only the distinct ones).

The product of its digits is 302400, while the sum is 48.

The spelling of 161921158725 in words is "one hundred sixty-one billion, nine hundred twenty-one million, one hundred fifty-eight thousand, seven hundred twenty-five".