81593870 has 16 divisors (see below), whose sum is σ = 146972448. Its totient is φ = 32614560.

The previous prime is 81593861. The next prime is 81593921. The reversal of 81593870 is 7839518.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23975 + ... + 27165.

It is an arithmetic number, because the mean of its divisors is an integer number (9185778).

Almost surely, 2^81593870 is an apocalyptic number.

81593870 is a deficient number, since it is larger than the sum of its proper divisors (65378578).

81593870 is a wasteful number, since it uses less digits than its factorization.

81593870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5755.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 81593870 is about 9032.9325249334. The cubic root of 81593870 is about 433.7297155455.

The spelling of 81593870 in words is "eighty-one million, five hundred ninety-three thousand, eight hundred seventy".