81888831 has 12 divisors (see below), whose sum is σ = 118484808. Its totient is φ = 54499824.

The previous prime is 81888827. The next prime is 81888839. The reversal of 81888831 is 13888818.

It is a happy number.

It is not a de Polignac number, because 81888831 - 2² = 81888827 is a prime.

It is a super-2 number, since 2×81888831² = 13411561285093122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81888839) 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, 1905 + ... + 12938.

It is an arithmetic number, because the mean of its divisors is an integer number (9873734).

Almost surely, 2^81888831 is an apocalyptic number.

81888831 is a deficient number, since it is larger than the sum of its proper divisors (36595977).

81888831 is a wasteful number, since it uses less digits than its factorization.

81888831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15462 (or 15459 counting only the distinct ones).

The product of its digits is 98304, while the sum is 45.

The square root of 81888831 is about 9049.2447751180. The cubic root of 81888831 is about 434.2517298432.

The spelling of 81888831 in words is "eighty-one million, eight hundred eighty-eight thousand, eight hundred thirty-one".