21002572 has 6 divisors (see below), whose sum is σ = 36754508. Its totient is φ = 10501284.

The previous prime is 21002567. The next prime is 21002573. The reversal of 21002572 is 27520012.

It is a super-2 number, since 2×21002572² = 882216061230368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625318 + ... + 2625325.

Almost surely, 2^21002572 is an apocalyptic number.

It is an amenable number.

21002572 is a deficient number, since it is larger than the sum of its proper divisors (15751936).

21002572 is a wasteful number, since it uses less digits than its factorization.

21002572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5250647 (or 5250645 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21002572 is about 4582.8563145706. The cubic root of 21002572 is about 275.9036805957.

Adding to 21002572 its reverse (27520012), we get a palindrome (48522584).

The spelling of 21002572 in words is "twenty-one million, two thousand, five hundred seventy-two".