21266951 has 2 divisors, whose sum is σ = 21266952. Its totient is φ = 21266950.

The previous prime is 21266941. The next prime is 21266953. The reversal of 21266951 is 15966212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21266951 - 2⁶ = 21266887 is a prime.

It is a Sophie Germain prime.

Together with 21266953, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21266953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633475 + 10633476.

It is an arithmetic number, because the mean of its divisors is an integer number (10633476).

Almost surely, 2^21266951 is an apocalyptic number.

21266951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21266951 is an equidigital number, since it uses as much as digits as its factorization.

21266951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 21266951 is about 4611.6104562289. The cubic root of 21266951 is about 277.0565424766.

The spelling of 21266951 in words is "twenty-one million, two hundred sixty-six thousand, nine hundred fifty-one".