21905266 has 16 divisors (see below), whose sum is σ = 34133400. Its totient is φ = 10530688.

The previous prime is 21905263. The next prime is 21905267. The reversal of 21905266 is 66250912.

It can be written as a sum of positive squares in 4 ways, for example, as 21818241 + 87025 = 4671^2 + 295^2 .

It is not an unprimeable number, because it can be changed into a prime (21905263) 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, 16350 + ... + 17638.

Almost surely, 2^21905266 is an apocalyptic number.

21905266 is a deficient number, since it is larger than the sum of its proper divisors (12228134).

21905266 is a wasteful number, since it uses less digits than its factorization.

21905266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1613.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21905266 is about 4680.3061865651. The cubic root of 21905266 is about 279.8011598488.

The spelling of 21905266 in words is "twenty-one million, nine hundred five thousand, two hundred sixty-six".