81011228556 has 12 divisors (see below), whose sum is σ = 189026199992. Its totient is φ = 27003742848.

The previous prime is 81011228539. The next prime is 81011228581. The reversal of 81011228556 is 65582211018.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3375467845 + ... + 3375467868.

Almost surely, 2^81011228556 is an apocalyptic number.

It is an amenable number.

81011228556 is an abundant number, since it is smaller than the sum of its proper divisors (108014971436).

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

81011228556 is a wasteful number, since it uses less digits than its factorization.

81011228556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6750935720 (or 6750935718 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 39.

The spelling of 81011228556 in words is "eighty-one billion, eleven million, two hundred twenty-eight thousand, five hundred fifty-six".