81570500 has 48 divisors (see below), whose sum is σ = 194358528. Its totient is φ = 29660000.

The previous prime is 81570493. The next prime is 81570563. The reversal of 81570500 is 507518.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81570500.

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 15 ways as a sum of consecutive naturals, for example, 1916 + ... + 12915.

It is an arithmetic number, because the mean of its divisors is an integer number (4049136).

Almost surely, 2^81570500 is an apocalyptic number.

It is an amenable number.

81570500 is an abundant number, since it is smaller than the sum of its proper divisors (112788028).

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

81570500 is a wasteful number, since it uses less digits than its factorization.

81570500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14861 (or 14849 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 26.

The square root of 81570500 is about 9031.6388324600. The cubic root of 81570500 is about 433.6883021756.

The spelling of 81570500 in words is "eighty-one million, five hundred seventy thousand, five hundred".