21207392 has 24 divisors (see below), whose sum is σ = 42285600. Its totient is φ = 10468224.

The previous prime is 21207377. The next prime is 21207421. The reversal of 21207392 is 29370212.

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, 1667 + ... + 6722.

It is an arithmetic number, because the mean of its divisors is an integer number (1761900).

Almost surely, 2^21207392 is an apocalyptic number.

It is an amenable number.

21207392 is a deficient number, since it is larger than the sum of its proper divisors (21078208).

21207392 is an equidigital number, since it uses as much as digits as its factorization.

21207392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8478 (or 8470 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21207392 is about 4605.1484232324. The cubic root of 21207392 is about 276.7976644529.

Subtracting 21207392 from its reverse (29370212), we obtain a triangular number (8162820 = T₄₀₄₀).

The spelling of 21207392 in words is "twenty-one million, two hundred seven thousand, three hundred ninety-two".