56721983994 has 64 divisors (see below), whose sum is σ = 136246279680. Its totient is φ = 17388457920.

The previous prime is 56721983957. The next prime is 56721984017. The reversal of 56721983994 is 49938912765.

56721983994 is a `hidden beast` number, since 56 + 7 + 2 + 198 + 399 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41164 + ... + 339320.

It is an arithmetic number, because the mean of its divisors is an integer number (2128848120).

Almost surely, 2^56721983994 is an apocalyptic number.

56721983994 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 56721983994, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68123139840).

56721983994 is an abundant number, since it is smaller than the sum of its proper divisors (79524295686).

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

56721983994 is a wasteful number, since it uses less digits than its factorization.

56721983994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298452 (or 298446 counting only the distinct ones).

The product of its digits is 29393280, while the sum is 63.

The spelling of 56721983994 in words is "fifty-six billion, seven hundred twenty-one million, nine hundred eighty-three thousand, nine hundred ninety-four".