21266955 has 20 divisors (see below), whose sum is σ = 38123712. Its totient is φ = 11342160.

The previous prime is 21266953. The next prime is 21266977. The reversal of 21266955 is 55966212.

It is not a de Polignac number, because 21266955 - 2¹ = 21266953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21266951) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25851 + ... + 26660.

Almost surely, 2^21266955 is an apocalyptic number.

21266955 is a deficient number, since it is larger than the sum of its proper divisors (16856757).

21266955 is an equidigital number, since it uses as much as digits as its factorization.

21266955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52528 (or 52519 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 21266955 is about 4611.6108899169. The cubic root of 21266955 is about 277.0565598467.

The spelling of 21266955 in words is "twenty-one million, two hundred sixty-six thousand, nine hundred fifty-five".