20756744640 has 112 divisors (see below), whose sum is σ = 73225212960. Its totient is φ = 5535129600.

The previous prime is 20756744633. The next prime is 20756744641. The reversal of 20756744640 is 4644765702.

20756744640 is a `hidden beast` number, since 2 + 0 + 7 + 567 + 4 + 46 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20756744641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1192561 + ... + 1209840.

Almost surely, 2^20756744640 is an apocalyptic number.

20756744640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20756744640 is an abundant number, since it is smaller than the sum of its proper divisors (52468468320).

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

20756744640 is a wasteful number, since it uses less digits than its factorization.

20756744640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2402427 (or 2402411 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 45.

The spelling of 20756744640 in words is "twenty billion, seven hundred fifty-six million, seven hundred forty-four thousand, six hundred forty".