81574851666 has 32 divisors (see below), whose sum is σ = 203407423488. Its totient is φ = 21188273040.

The previous prime is 81574851643. The next prime is 81574851691. The reversal of 81574851666 is 66615847518.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88284010 + ... + 88284933.

It is an arithmetic number, because the mean of its divisors is an integer number (6356481984).

Almost surely, 2^81574851666 is an apocalyptic number.

81574851666 is an abundant number, since it is smaller than the sum of its proper divisors (121832571822).

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

81574851666 is a wasteful number, since it uses less digits than its factorization.

81574851666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176568966.

The product of its digits is 9676800, while the sum is 57.

The spelling of 81574851666 in words is "eighty-one billion, five hundred seventy-four million, eight hundred fifty-one thousand, six hundred sixty-six".