81397351228 has 48 divisors (see below), whose sum is σ = 151738725600. Its totient is φ = 38072846336.

The previous prime is 81397351219. The next prime is 81397351241. The reversal of 81397351228 is 82215379318.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17506248 + ... + 17510896.

It is an arithmetic number, because the mean of its divisors is an integer number (3161223450).

Almost surely, 2^81397351228 is an apocalyptic number.

It is an amenable number.

81397351228 is a deficient number, since it is larger than the sum of its proper divisors (70341374372).

81397351228 is a wasteful number, since it uses less digits than its factorization.

81397351228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6174 (or 6172 counting only the distinct ones).

The product of its digits is 725760, while the sum is 49.

The spelling of 81397351228 in words is "eighty-one billion, three hundred ninety-seven million, three hundred fifty-one thousand, two hundred twenty-eight".