21386279 has 2 divisors, whose sum is σ = 21386280. Its totient is φ = 21386278.

The previous prime is 21386263. The next prime is 21386291. The reversal of 21386279 is 97268312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21386279 - 2⁴ = 21386263 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21386219) 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, 10693139 + 10693140.

It is an arithmetic number, because the mean of its divisors is an integer number (10693140).

Almost surely, 2^21386279 is an apocalyptic number.

21386279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21386279 is an equidigital number, since it uses as much as digits as its factorization.

21386279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 21386279 is about 4624.5301382951. The cubic root of 21386279 is about 277.5737606591.

The spelling of 21386279 in words is "twenty-one million, three hundred eighty-six thousand, two hundred seventy-nine".