81570992 has 20 divisors (see below), whose sum is σ = 159822360. Its totient is φ = 40326528.

The previous prime is 81570967. The next prime is 81571027. The reversal of 81570992 is 29907518.

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, 27218 + ... + 30065.

It is an arithmetic number, because the mean of its divisors is an integer number (7991118).

Almost surely, 2^81570992 is an apocalyptic number.

It is an amenable number.

81570992 is a deficient number, since it is larger than the sum of its proper divisors (78251368).

81570992 is a wasteful number, since it uses less digits than its factorization.

81570992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57380 (or 57374 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 81570992 is about 9031.6660700006. Note that the first 3 decimals coincide. The cubic root of 81570992 is about 433.6891741176.

The spelling of 81570992 in words is "eighty-one million, five hundred seventy thousand, nine hundred ninety-two".