20749554864 has 100 divisors (see below), whose sum is σ = 61520151000. Its totient is φ = 6747805440.

The previous prime is 20749554851. The next prime is 20749554869. The reversal of 20749554864 is 46845594702.

20749554864 is a `hidden beast` number, since 2 + 0 + 7 + 4 + 9 + 554 + 86 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 20749554864.

It is not an unprimeable number, because it can be changed into a prime (20749554869) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 142114 + ... + 248385.

It is an arithmetic number, because the mean of its divisors is an integer number (615201510).

Almost surely, 2^20749554864 is an apocalyptic number.

20749554864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20749554864 is an abundant number, since it is smaller than the sum of its proper divisors (40770596136).

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

20749554864 is a wasteful number, since it uses less digits than its factorization.

20749554864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390560 (or 390545 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 54.

It can be divided in two parts, 20 and 749554864, that added together give a square (749554884 = 27378²).

The spelling of 20749554864 in words is "twenty billion, seven hundred forty-nine million, five hundred fifty-four thousand, eight hundred sixty-four".