21165379 has 2 divisors, whose sum is σ = 21165380. Its totient is φ = 21165378.

The previous prime is 21165299. The next prime is 21165383. The reversal of 21165379 is 97356112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21165379 - 2⁷ = 21165251 is a prime.

It is not a weakly prime, because it can be changed into another prime (21165479) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10582689 + 10582690.

It is an arithmetic number, because the mean of its divisors is an integer number (10582690).

Almost surely, 2^21165379 is an apocalyptic number.

21165379 is a deficient number, since it is larger than the sum of its proper divisors (1).

21165379 is an equidigital number, since it uses as much as digits as its factorization.

21165379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 34.

The square root of 21165379 is about 4600.5846367609. The cubic root of 21165379 is about 276.6147598626.

The spelling of 21165379 in words is "twenty-one million, one hundred sixty-five thousand, three hundred seventy-nine".