21268210 has 16 divisors (see below), whose sum is σ = 38353176. Its totient is φ = 8491648.

The previous prime is 21268193. The next prime is 21268213. The reversal of 21268210 is 1286212.

It can be written as a sum of positive squares in 4 ways, for example, as 17952169 + 3316041 = 4237^2 + 1821^2 .

It is not an unprimeable number, because it can be changed into a prime (21268213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4902 + ... + 8158.

Almost surely, 2^21268210 is an apocalyptic number.

21268210 is a deficient number, since it is larger than the sum of its proper divisors (17084966).

21268210 is a wasteful number, since it uses less digits than its factorization.

21268210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3917.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21268210 is about 4611.7469574989. The cubic root of 21268210 is about 277.0620096027.

The spelling of 21268210 in words is "twenty-one million, two hundred sixty-eight thousand, two hundred ten".