81864331 has 12 divisors (see below), whose sum is σ = 88523064. Its totient is φ = 75650400.

The previous prime is 81864301. The next prime is 81864347. The reversal of 81864331 is 13346818.

It is not a de Polignac number, because 81864331 - 2¹¹ = 81862283 is a prime.

It is a super-2 number, since 2×81864331² = 13403537380155122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81864301) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12036 + ... + 17566.

It is an arithmetic number, because the mean of its divisors is an integer number (7376922).

Almost surely, 2^81864331 is an apocalyptic number.

81864331 is a deficient number, since it is larger than the sum of its proper divisors (6658733).

81864331 is a wasteful number, since it uses less digits than its factorization.

81864331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5610 (or 5591 counting only the distinct ones).

The product of its digits is 13824, while the sum is 34.

The square root of 81864331 is about 9047.8909697233. The cubic root of 81864331 is about 434.2084181629.

The spelling of 81864331 in words is "eighty-one million, eight hundred sixty-four thousand, three hundred thirty-one".