20751909505656 has 128 divisors (see below), whose sum is σ = 59457540710400. Its totient is φ = 5912502906240.

The previous prime is 20751909505637. The next prime is 20751909505693. The reversal of 20751909505656 is 65650590915702.

It is a self number, because there is not a number n which added to its sum of digits gives 20751909505656.

It is a congruent number.

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, 87125655 + ... + 87363513.

It is an arithmetic number, because the mean of its divisors is an integer number (464512036800).

Almost surely, 2^{20751909505656} is an apocalyptic number.

It is an amenable number.

20751909505656 is an abundant number, since it is smaller than the sum of its proper divisors (38705631204744).

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

20751909505656 is a wasteful number, since it uses less digits than its factorization.

20751909505656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239329 (or 239325 counting only the distinct ones).

The product of its (nonzero) digits is 25515000, while the sum is 60.

The spelling of 20751909505656 in words is "twenty trillion, seven hundred fifty-one billion, nine hundred nine million, five hundred five thousand, six hundred fifty-six".