81015312 has 40 divisors (see below), whose sum is σ = 239189056. Its totient is φ = 23147136.

The previous prime is 81015293. The next prime is 81015313. The reversal of 81015312 is 21351018.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81015313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120223 + ... + 120894.

Almost surely, 2^81015312 is an apocalyptic number.

It is an amenable number.

81015312 is an abundant number, since it is smaller than the sum of its proper divisors (158173744).

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

81015312 is a wasteful number, since it uses less digits than its factorization.

81015312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241135 (or 241129 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 81015312 is about 9000.8506264686. The cubic root of 81015312 is about 432.7021332330.

The spelling of 81015312 in words is "eighty-one million, fifteen thousand, three hundred twelve".