81137881266 has 16 divisors (see below), whose sum is σ = 174758513664. Its totient is φ = 24965501904.

The previous prime is 81137881213. The next prime is 81137881271. The reversal of 81137881266 is 66218873118.

It is a happy 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, 520114546 + ... + 520114701.

It is an arithmetic number, because the mean of its divisors is an integer number (10922407104).

Almost surely, 2^81137881266 is an apocalyptic number.

81137881266 is an abundant number, since it is smaller than the sum of its proper divisors (93620632398).

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

81137881266 is a wasteful number, since it uses less digits than its factorization.

81137881266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040229265.

The product of its digits is 774144, while the sum is 51.

The spelling of 81137881266 in words is "eighty-one billion, one hundred thirty-seven million, eight hundred eighty-one thousand, two hundred sixty-six".