81931032 has 48 divisors (see below), whose sum is σ = 229554000. Its totient is φ = 26367936.

The previous prime is 81931013. The next prime is 81931033. The reversal of 81931032 is 23013918.

It is a junction number, because it is equal to n+sod(n) for n = 81930987 and 81931005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81931033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17532 + ... + 21707.

It is an arithmetic number, because the mean of its divisors is an integer number (4782375).

Almost surely, 2^81931032 is an apocalyptic number.

It is an amenable number.

81931032 is an abundant number, since it is smaller than the sum of its proper divisors (147622968).

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

81931032 is a wasteful number, since it uses less digits than its factorization.

81931032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39280 (or 39273 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 81931032 is about 9051.5762163283. The cubic root of 81931032 is about 434.3263135191.

The spelling of 81931032 in words is "eighty-one million, nine hundred thirty-one thousand, thirty-two".