81866872590 has 64 divisors (see below), whose sum is σ = 201338609472. Its totient is φ = 21291724800.

The previous prime is 81866872583. The next prime is 81866872639. The reversal of 81866872590 is 9527866818.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4508730 + ... + 4526850.

It is an arithmetic number, because the mean of its divisors is an integer number (3145915773).

Almost surely, 2^81866872590 is an apocalyptic number.

81866872590 is an abundant number, since it is smaller than the sum of its proper divisors (119471736882).

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

81866872590 is a wasteful number, since it uses less digits than its factorization.

81866872590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21845.

The product of its (nonzero) digits is 11612160, while the sum is 60.

The spelling of 81866872590 in words is "eighty-one billion, eight hundred sixty-six million, eight hundred seventy-two thousand, five hundred ninety".