81438512 has 20 divisors (see below), whose sum is σ = 158245080. Its totient is φ = 40601088.

The previous prime is 81438509. The next prime is 81438523. The reversal of 81438512 is 21583418.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1562 + ... + 12857.

It is an arithmetic number, because the mean of its divisors is an integer number (7912254).

Almost surely, 2^81438512 is an apocalyptic number.

It is an amenable number.

81438512 is a deficient number, since it is larger than the sum of its proper divisors (76806568).

81438512 is a wasteful number, since it uses less digits than its factorization.

81438512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14780 (or 14774 counting only the distinct ones).

The product of its digits is 7680, while the sum is 32.

The square root of 81438512 is about 9024.3288947157. The cubic root of 81438512 is about 433.4542610563.

The spelling of 81438512 in words is "eighty-one million, four hundred thirty-eight thousand, five hundred twelve".