81631088 has 80 divisors (see below), whose sum is σ = 198844416. Its totient is φ = 31537920.

The previous prime is 81631073. The next prime is 81631097. The reversal of 81631088 is 88013618.

It is a happy number.

It is a congruent number.

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, 212945 + ... + 213327.

Almost surely, 2^81631088 is an apocalyptic number.

81631088 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81631088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99422208).

81631088 is an abundant number, since it is smaller than the sum of its proper divisors (117213328).

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

81631088 is a wasteful number, since it uses less digits than its factorization.

81631088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582 (or 576 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 81631088 is about 9034.9924183698. The cubic root of 81631088 is about 433.7956522748.

The spelling of 81631088 in words is "eighty-one million, six hundred thirty-one thousand, eighty-eight".