161801931 has 8 divisors (see below), whose sum is σ = 217184400. Its totient is φ = 107143712.

The previous prime is 161801923. The next prime is 161801953. The reversal of 161801931 is 139108161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161801931 - 2³ = 161801923 is a prime.

It is a super-2 number, since 2×161801931² = 52359729750657522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161801921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180540 + ... + 181433.

It is an arithmetic number, because the mean of its divisors is an integer number (27148050).

Almost surely, 2^161801931 is an apocalyptic number.

161801931 is a deficient number, since it is larger than the sum of its proper divisors (55382469).

161801931 is a wasteful number, since it uses less digits than its factorization.

161801931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362125.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 161801931 is about 12720.1387964126. The cubic root of 161801931 is about 544.9139173301.

The spelling of 161801931 in words is "one hundred sixty-one million, eight hundred one thousand, nine hundred thirty-one".