81221272677 has 24 divisors (see below), whose sum is σ = 119186121600. Its totient is φ = 53288796960.

The previous prime is 81221272607. The next prime is 81221272681. The reversal of 81221272677 is 77627212218.

It is not a de Polignac number, because 81221272677 - 2⁸ = 81221272421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81221272607) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 241824 + ... + 470022.

It is an arithmetic number, because the mean of its divisors is an integer number (4966088400).

Almost surely, 2^81221272677 is an apocalyptic number.

It is an amenable number.

81221272677 is a deficient number, since it is larger than the sum of its proper divisors (37964848923).

81221272677 is a wasteful number, since it uses less digits than its factorization.

81221272677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228833 (or 228830 counting only the distinct ones).

The product of its digits is 263424, while the sum is 45.

The spelling of 81221272677 in words is "eighty-one billion, two hundred twenty-one million, two hundred seventy-two thousand, six hundred seventy-seven".