2121565824 has 128 divisors (see below), whose sum is σ = 7156156800. Its totient is φ = 606154752.

The previous prime is 2121565811. The next prime is 2121565841. The reversal of 2121565824 is 4285651212.

2121565824 is a `hidden beast` number, since 2 + 1 + 21 + 56 + 582 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19657 + ... + 68040.

It is an arithmetic number, because the mean of its divisors is an integer number (55907475).

Almost surely, 2^2121565824 is an apocalyptic number.

2121565824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

2121565824 is an abundant number, since it is smaller than the sum of its proper divisors (5034590976).

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

2121565824 is an equidigital number, since it uses as much as digits as its factorization.

2121565824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87727 (or 87709 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 2121565824 is about 46060.4583563820. The cubic root of 2121565824 is about 1284.9478545762.

The spelling of 2121565824 in words is "two billion, one hundred twenty-one million, five hundred sixty-five thousand, eight hundred twenty-four".