81931260 has 48 divisors (see below), whose sum is σ = 230025600. Its totient is φ = 21789504.

The previous prime is 81931259. The next prime is 81931261. The reversal of 81931260 is 6213918.

It is an interprime number because it is at equal distance from previous prime (81931259) and next prime (81931261).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81931261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23511 + ... + 26769.

It is an arithmetic number, because the mean of its divisors is an integer number (4792200).

Almost surely, 2^81931260 is an apocalyptic number.

It is an amenable number.

81931260 is an abundant number, since it is smaller than the sum of its proper divisors (148094340).

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

81931260 is a wasteful number, since it uses less digits than its factorization.

81931260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3690 (or 3688 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 81931260 is about 9051.5888108111. The cubic root of 81931260 is about 434.3267164039.

It can be divided in two parts, 8193 and 1260, that added together give a triangular number (9453 = T₁₃₇).

The spelling of 81931260 in words is "eighty-one million, nine hundred thirty-one thousand, two hundred sixty".