21573579204 has 30 divisors (see below), whose sum is σ = 56397598334. Its totient is φ = 7191192960.

The previous prime is 21573579193. The next prime is 21573579217. The reversal of 21573579204 is 40297537512.

It is a happy number.

21573579204 is a `hidden beast` number, since 2 + 1 + 5 + 73 + 579 + 2 + 0 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21447016704 + 126562500 = 146448^2 + 11250^2 .

It is a super-2 number, since 2×21573579204² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21573579204.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 33292237 + ... + 33292884.

Almost surely, 2^21573579204 is an apocalyptic number.

It is an amenable number.

21573579204 is an abundant number, since it is smaller than the sum of its proper divisors (34824019130).

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

21573579204 is a wasteful number, since it uses less digits than its factorization.

21573579204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66585137 (or 66585126 counting only the distinct ones).

The product of its (nonzero) digits is 529200, while the sum is 45.

The spelling of 21573579204 in words is "twenty-one billion, five hundred seventy-three million, five hundred seventy-nine thousand, two hundred four".