21506572252 has 12 divisors (see below), whose sum is σ = 41058001656. Its totient is φ = 9775714640.

The previous prime is 21506572229. The next prime is 21506572271. The reversal of 21506572252 is 25227560512.

It is a congruent number.

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, 244392823 + ... + 244392910.

It is an arithmetic number, because the mean of its divisors is an integer number (3421500138).

Almost surely, 2^21506572252 is an apocalyptic number.

21506572252 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21506572252 is a deficient number, since it is larger than the sum of its proper divisors (19551429404).

21506572252 is a wasteful number, since it uses less digits than its factorization.

21506572252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488785748 (or 488785746 counting only the distinct ones).

The product of its (nonzero) digits is 84000, while the sum is 37.

The spelling of 21506572252 in words is "twenty-one billion, five hundred six million, five hundred seventy-two thousand, two hundred fifty-two".