20451583856 has 80 divisors (see below), whose sum is σ = 43601646816. Its totient is φ = 9216000000.

The previous prime is 20451583813. The next prime is 20451583871. The reversal of 20451583856 is 65838515402.

It is a self number, because there is not a number n which added to its sum of digits gives 20451583856.

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, 12773456 + ... + 12775056.

Almost surely, 2^20451583856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20451583856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21800823408).

20451583856 is an abundant number, since it is smaller than the sum of its proper divisors (23150062960).

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

20451583856 is a wasteful number, since it uses less digits than its factorization.

20451583856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2202 (or 2196 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 47.

The spelling of 20451583856 in words is "twenty billion, four hundred fifty-one million, five hundred eighty-three thousand, eight hundred fifty-six".