21252204 has 36 divisors (see below), whose sum is σ = 53892384. Its totient is φ = 7061472.

The previous prime is 21252167. The next prime is 21252211. The reversal of 21252204 is 40225212.

Added to its reverse (40225212) it gives a triangular number (61477416 = T₁₁₀₈₈).

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13549 + ... + 15035.

Almost surely, 2^21252204 is an apocalyptic number.

It is an amenable number.

21252204 is an abundant number, since it is smaller than the sum of its proper divisors (32640180).

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

21252204 is a wasteful number, since it uses less digits than its factorization.

21252204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1894 (or 1889 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21252204 is about 4610.0112798127. The cubic root of 21252204 is about 276.9924885120.

Adding to 21252204 its reverse (40225212), we get a palindrome (61477416).

The spelling of 21252204 in words is "twenty-one million, two hundred fifty-two thousand, two hundred four".