86561931 has 4 divisors (see below), whose sum is σ = 115415912. Its totient is φ = 57707952.

The previous prime is 86561911. The next prime is 86561939. The reversal of 86561931 is 13916568.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 86561931 - 2⁵ = 86561899 is a prime.

It is a super-2 number, since 2×86561931² = 14985935796897522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 86561931.

It is not an unprimeable number, because it can be changed into a prime (86561939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14426986 + ... + 14426991.

It is an arithmetic number, because the mean of its divisors is an integer number (28853978).

Almost surely, 2^86561931 is an apocalyptic number.

86561931 is a deficient number, since it is larger than the sum of its proper divisors (28853981).

86561931 is a wasteful number, since it uses less digits than its factorization.

86561931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28853980.

The product of its digits is 38880, while the sum is 39.

The square root of 86561931 is about 9303.8664543296. The cubic root of 86561931 is about 442.3597921524.

The spelling of 86561931 in words is "eighty-six million, five hundred sixty-one thousand, nine hundred thirty-one".