21266879 has 4 divisors (see below), whose sum is σ = 21536160. Its totient is φ = 20997600.

The previous prime is 21266873. The next prime is 21266887. The reversal of 21266879 is 97866212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21266879 - 2²⁴ = 4489663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134522 + ... + 134679.

It is an arithmetic number, because the mean of its divisors is an integer number (5384040).

Almost surely, 2^21266879 is an apocalyptic number.

21266879 is a deficient number, since it is larger than the sum of its proper divisors (269281).

21266879 is an equidigital number, since it uses as much as digits as its factorization.

21266879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269280.

The product of its digits is 72576, while the sum is 41.

The square root of 21266879 is about 4611.6026498388. The cubic root of 21266879 is about 277.0562298148.

The spelling of 21266879 in words is "twenty-one million, two hundred sixty-six thousand, eight hundred seventy-nine".