21421379 has 24 divisors (see below), whose sum is σ = 26517600. Its totient is φ = 17294256.

The previous prime is 21421373. The next prime is 21421397. The reversal of 21421379 is 97312412.

It is not a de Polignac number, because 21421379 - 2⁸ = 21421123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21421373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123737 + ... + 123909.

It is an arithmetic number, because the mean of its divisors is an integer number (1104900).

Almost surely, 2^21421379 is an apocalyptic number.

21421379 is a deficient number, since it is larger than the sum of its proper divisors (5096221).

21421379 is an equidigital number, since it uses as much as digits as its factorization.

21421379 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 199 counting only the distinct ones).

The product of its digits is 3024, while the sum is 29.

The square root of 21421379 is about 4628.3235625872. The cubic root of 21421379 is about 277.7255326394.

The spelling of 21421379 in words is "twenty-one million, four hundred twenty-one thousand, three hundred seventy-nine".