21872210 has 16 divisors (see below), whose sum is σ = 39441600. Its totient is φ = 8732976.

The previous prime is 21872209. The next prime is 21872231. The reversal of 21872210 is 1227812.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4931 + ... + 8249.

It is an arithmetic number, because the mean of its divisors is an integer number (2465100).

Almost surely, 2^21872210 is an apocalyptic number.

21872210 is a deficient number, since it is larger than the sum of its proper divisors (17569390).

21872210 is a wasteful number, since it uses less digits than its factorization.

21872210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3985.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21872210 is about 4676.7734604105. The cubic root of 21872210 is about 279.6603449495.

The spelling of 21872210 in words is "twenty-one million, eight hundred seventy-two thousand, two hundred ten".