21012120224 has 24 divisors (see below), whose sum is σ = 43801001748. Its totient is φ = 9888056320.

The previous prime is 21012120211. The next prime is 21012120257. The reversal of 21012120224 is 42202121012.

It can be written as a sum of positive squares in 2 ways, for example, as 20972832400 + 39287824 = 144820^2 + 6268^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19312067 + ... + 19313154.

Almost surely, 2^21012120224 is an apocalyptic number.

It is an amenable number.

21012120224 is an abundant number, since it is smaller than the sum of its proper divisors (22788881524).

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

21012120224 is a wasteful number, since it uses less digits than its factorization.

21012120224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38625248 (or 38625240 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21012120224 its reverse (42202121012), we get a palindrome (63214241236).

The spelling of 21012120224 in words is "twenty-one billion, twelve million, one hundred twenty thousand, two hundred twenty-four".