81310012 has 36 divisors (see below), whose sum is σ = 166149984. Its totient is φ = 34715520.

The previous prime is 81310001. The next prime is 81310013. The reversal of 81310012 is 21001318.

It is a super-2 number, since 2×81310012² = 13222636102880288, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81310013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65437 + ... + 66667.

Almost surely, 2^81310012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81310012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83074992).

81310012 is an abundant number, since it is smaller than the sum of its proper divisors (84839972).

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

81310012 is a wasteful number, since it uses less digits than its factorization.

81310012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1586 (or 1577 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 81310012 is about 9017.2064410215. The cubic root of 81310012 is about 433.2261617938.

The spelling of 81310012 in words is "eighty-one million, three hundred ten thousand, twelve".