81510506918 has 16 divisors (see below), whose sum is σ = 123102050400. Its totient is φ = 40476560256.

The previous prime is 81510506809. The next prime is 81510506923. The reversal of 81510506918 is 81960501518.

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, 3523646 + ... + 3546702.

It is an arithmetic number, because the mean of its divisors is an integer number (7693878150).

Almost surely, 2^81510506918 is an apocalyptic number.

81510506918 is a deficient number, since it is larger than the sum of its proper divisors (41591543482).

81510506918 is a wasteful number, since it uses less digits than its factorization.

81510506918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35071.

The product of its (nonzero) digits is 86400, while the sum is 44.

The spelling of 81510506918 in words is "eighty-one billion, five hundred ten million, five hundred six thousand, nine hundred eighteen".