21207572 has 12 divisors (see below), whose sum is σ = 39066720. Its totient is φ = 10045656.

The previous prime is 21207569. The next prime is 21207581. The reversal of 21207572 is 27570212.

It is a super-2 number, since 2×21207572² = 899522220270368, which contains 22 as substring.

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, 139448 + ... + 139599.

It is an arithmetic number, because the mean of its divisors is an integer number (3255560).

Almost surely, 2^21207572 is an apocalyptic number.

It is an amenable number.

21207572 is a deficient number, since it is larger than the sum of its proper divisors (17859148).

21207572 is a wasteful number, since it uses less digits than its factorization.

21207572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279070 (or 279068 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 21207572 is about 4605.1679665350. The cubic root of 21207572 is about 276.7984475672.

Adding to 21207572 its reverse (27570212), we get a palindrome (48777784).

The spelling of 21207572 in words is "twenty-one million, two hundred seven thousand, five hundred seventy-two".