21339379 has 2 divisors, whose sum is σ = 21339380. Its totient is φ = 21339378.

The previous prime is 21339371. The next prime is 21339391. The reversal of 21339379 is 97393312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21339379 - 2³ = 21339371 is a prime.

It is a super-2 number, since 2×21339379² = 910738192211282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21339371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10669689 + 10669690.

It is an arithmetic number, because the mean of its divisors is an integer number (10669690).

Almost surely, 2^21339379 is an apocalyptic number.

21339379 is a deficient number, since it is larger than the sum of its proper divisors (1).

21339379 is an equidigital number, since it uses as much as digits as its factorization.

21339379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30618, while the sum is 37.

The square root of 21339379 is about 4619.4565697710. The cubic root of 21339379 is about 277.3707062105.

The spelling of 21339379 in words is "twenty-one million, three hundred thirty-nine thousand, three hundred seventy-nine".