81457564 has 6 divisors (see below), whose sum is σ = 142550744. Its totient is φ = 40728780.

The previous prime is 81457547. The next prime is 81457567. The reversal of 81457564 is 46575418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81457567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10182192 + ... + 10182199.

Almost surely, 2^81457564 is an apocalyptic number.

It is an amenable number.

81457564 is a deficient number, since it is larger than the sum of its proper divisors (61093180).

81457564 is a wasteful number, since it uses less digits than its factorization.

81457564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20364395 (or 20364393 counting only the distinct ones).

The product of its digits is 134400, while the sum is 40.

The square root of 81457564 is about 9025.3844239456. The cubic root of 81457564 is about 433.4880596711.

The spelling of 81457564 in words is "eighty-one million, four hundred fifty-seven thousand, five hundred sixty-four".