21122859 has 4 divisors (see below), whose sum is σ = 28163816. Its totient is φ = 14081904.

The previous prime is 21122821. The next prime is 21122863. The reversal of 21122859 is 95822112.

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

It is not a de Polignac number, because 21122859 - 2⁸ = 21122603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21122869) 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, 3520474 + ... + 3520479.

It is an arithmetic number, because the mean of its divisors is an integer number (7040954).

Almost surely, 2^21122859 is an apocalyptic number.

21122859 is a deficient number, since it is larger than the sum of its proper divisors (7040957).

21122859 is an equidigital number, since it uses as much as digits as its factorization.

21122859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7040956.

The product of its digits is 2880, while the sum is 30.

The square root of 21122859 is about 4595.9611617158. The cubic root of 21122859 is about 276.4294014281.

The spelling of 21122859 in words is "twenty-one million, one hundred twenty-two thousand, eight hundred fifty-nine".