81438587886 has 32 divisors (see below), whose sum is σ = 164472197760. Its totient is φ = 26880584096.

The previous prime is 81438587869. The next prime is 81438587897. The reversal of 81438587886 is 68878583418.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1486285 + ... + 1540103.

It is an arithmetic number, because the mean of its divisors is an integer number (5139756180).

Almost surely, 2^81438587886 is an apocalyptic number.

81438587886 is an abundant number, since it is smaller than the sum of its proper divisors (83033609874).

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

81438587886 is a wasteful number, since it uses less digits than its factorization.

81438587886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56288.

The product of its digits is 82575360, while the sum is 66.

The spelling of 81438587886 in words is "eighty-one billion, four hundred thirty-eight million, five hundred eighty-seven thousand, eight hundred eighty-six".