21805573252 has 12 divisors (see below), whose sum is σ = 38174397660. Its totient is φ = 10898602496.

The previous prime is 21805573247. The next prime is 21805573253. The reversal of 21805573252 is 25237550812.

It can be written as a sum of positive squares in 2 ways, for example, as 12127735876 + 9677837376 = 110126^2 + 98376^2 .

It is not an unprimeable number, because it can be changed into a prime (21805573253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1034293 + ... + 1055164.

It is an arithmetic number, because the mean of its divisors is an integer number (3181199805).

Almost surely, 2^21805573252 is an apocalyptic number.

It is an amenable number.

21805573252 is a deficient number, since it is larger than the sum of its proper divisors (16368824408).

21805573252 is a wasteful number, since it uses less digits than its factorization.

21805573252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2092070 (or 2092068 counting only the distinct ones).

The product of its (nonzero) digits is 168000, while the sum is 40.

The spelling of 21805573252 in words is "twenty-one billion, eight hundred five million, five hundred seventy-three thousand, two hundred fifty-two".