81921734848 has 56 divisors (see below), whose sum is σ = 167859699840. Its totient is φ = 39627202560.

The previous prime is 81921734729. The next prime is 81921734897. The reversal of 81921734848 is 84843712918.

It is a super-2 number, since 2×81921734848² (a number of 23 digits) contains 22 as substring.

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, 12243888 + ... + 12250576.

It is an arithmetic number, because the mean of its divisors is an integer number (2997494640).

Almost surely, 2^81921734848 is an apocalyptic number.

It is an amenable number.

81921734848 is an abundant number, since it is smaller than the sum of its proper divisors (85937964992).

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

81921734848 is a wasteful number, since it uses less digits than its factorization.

81921734848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12905 (or 12895 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 55.

The spelling of 81921734848 in words is "eighty-one billion, nine hundred twenty-one million, seven hundred thirty-four thousand, eight hundred forty-eight".