56438572778721 has 63 divisors (see below), whose sum is σ = 98436997410051. Its totient is φ = 32249801659824.

The previous prime is 56438572778711. The next prime is 56438572778723. The reversal of 56438572778721 is 12787727583465.

The square root of 56438572778721 is 7512561.

It is a perfect power (a square), and thus also a powerful number.

56438572778721 is a `hidden beast` number, since 5 + 6 + 43 + 8 + 572 + 7 + 7 + 8 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 43132857488721 + 13305715290000 = 6567561^2 + 3647700^2 .

It is a tau number, because it is divible by the number of its divisors (63).

It is a de Polignac number, because none of the positive numbers 2^k-56438572778721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 56438572778721.

It is not an unprimeable number, because it can be changed into a prime (56438572778723) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 1419854155 + ... + 1419893903.

Almost surely, 2^{56438572778721} is an apocalyptic number.

56438572778721 is the 7512561-st square number.

56438572778721 is the 3756281-st centered octagonal number.

It is an amenable number.

56438572778721 is a deficient number, since it is larger than the sum of its proper divisors (41998424631330).

56438572778721 is an frugal number, since it uses more digits than its factorization.

56438572778721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79530 (or 39759 counting only the distinct ones).

The product of its digits is 1106380800, while the sum is 72.

The spelling of 56438572778721 in words is "fifty-six trillion, four hundred thirty-eight billion, five hundred seventy-two million, seven hundred seventy-eight thousand, seven hundred twenty-one".