161531891610 has 32 divisors (see below), whose sum is σ = 389706273792. Its totient is φ = 42849645120.

The previous prime is 161531891597. The next prime is 161531891623. The reversal of 161531891610 is 16198135161.

It is an interprime number because it is at equal distance from previous prime (161531891597) and next prime (161531891623).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14089549 + ... + 14101008.

It is an arithmetic number, because the mean of its divisors is an integer number (12178321056).

Almost surely, 2^161531891610 is an apocalyptic number.

161531891610 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161531891610 is an abundant number, since it is smaller than the sum of its proper divisors (228174382182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161531891610 is a wasteful number, since it uses less digits than its factorization.

161531891610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28190758.

The product of its (nonzero) digits is 38880, while the sum is 42.

The spelling of 161531891610 in words is "one hundred sixty-one billion, five hundred thirty-one million, eight hundred ninety-one thousand, six hundred ten".