21271379 has 2 divisors, whose sum is σ = 21271380. Its totient is φ = 21271378.

The previous prime is 21271351. The next prime is 21271381. The reversal of 21271379 is 97317212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21271379 is a prime.

Together with 21271381, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21271319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10635689 + 10635690.

It is an arithmetic number, because the mean of its divisors is an integer number (10635690).

Almost surely, 2^21271379 is an apocalyptic number.

21271379 is a deficient number, since it is larger than the sum of its proper divisors (1).

21271379 is an equidigital number, since it uses as much as digits as its factorization.

21271379 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5292, while the sum is 32.

The square root of 21271379 is about 4612.0905238297. The cubic root of 21271379 is about 277.0757698251.

The spelling of 21271379 in words is "twenty-one million, two hundred seventy-one thousand, three hundred seventy-nine".