20757565440 has 624 divisors, whose sum is σ = 77137988928. Its totient is φ = 5350883328.

The previous prime is 20757565351. The next prime is 20757565453. The reversal of 20757565440 is 4456575702.

20757565440 is a `hidden beast` number, since 2 + 0 + 7 + 57 + 56 + 544 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 213995472 + ... + 213995568.

It is an arithmetic number, because the mean of its divisors is an integer number (123618572).

Almost surely, 2^20757565440 is an apocalyptic number.

20757565440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20757565440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38568994464).

20757565440 is an abundant number, since it is smaller than the sum of its proper divisors (56380423488).

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

20757565440 is an frugal number, since it uses more digits than its factorization.

20757565440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 1176000, while the sum is 45.

The spelling of 20757565440 in words is "twenty billion, seven hundred fifty-seven million, five hundred sixty-five thousand, four hundred forty".