2121564456 has 48 divisors (see below), whose sum is σ = 6268260960. Its totient is φ = 642898080.

The previous prime is 2121564437. The next prime is 2121564457. The reversal of 2121564456 is 6544651212.

2121564456 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 5 + 644 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 2121564456.

It is not an unprimeable number, because it can be changed into a prime (2121564457) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1338580 + ... + 1340163.

It is an arithmetic number, because the mean of its divisors is an integer number (130588770).

Almost surely, 2^2121564456 is an apocalyptic number.

It is an amenable number.

2121564456 is an abundant number, since it is smaller than the sum of its proper divisors (4146696504).

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

2121564456 is a wasteful number, since it uses less digits than its factorization.

2121564456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2678766 (or 2678759 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 2121564456 is about 46060.4435063320. The cubic root of 2121564456 is about 1284.9475783951.

It can be divided in two parts, 212156 and 4456, that added together give a palindrome (216612).

The spelling of 2121564456 in words is "two billion, one hundred twenty-one million, five hundred sixty-four thousand, four hundred fifty-six".