21365210 has 16 divisors (see below), whose sum is σ = 38762496. Its totient is φ = 8478288.

The previous prime is 21365203. The next prime is 21365219. The reversal of 21365210 is 1256312.

It is not an unprimeable number, because it can be changed into a prime (21365219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7142 + ... + 9681.

It is an arithmetic number, because the mean of its divisors is an integer number (2422656).

Almost surely, 2^21365210 is an apocalyptic number.

21365210 is a deficient number, since it is larger than the sum of its proper divisors (17397286).

21365210 is a wasteful number, since it uses less digits than its factorization.

21365210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16957.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21365210 is about 4622.2516158253. The cubic root of 21365210 is about 277.4825787835.

The spelling of 21365210 in words is "twenty-one million, three hundred sixty-five thousand, two hundred ten".