21365759 has 2 divisors, whose sum is σ = 21365760. Its totient is φ = 21365758.

The previous prime is 21365749. The next prime is 21365767. The reversal of 21365759 is 95756312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21365759 - 2²⁴ = 4588543 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21365749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682879 + 10682880.

It is an arithmetic number, because the mean of its divisors is an integer number (10682880).

Almost surely, 2^21365759 is an apocalyptic number.

21365759 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365759 is an equidigital number, since it uses as much as digits as its factorization.

21365759 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56700, while the sum is 38.

The square root of 21365759 is about 4622.3110020854. The cubic root of 21365759 is about 277.4849554920.

The spelling of 21365759 in words is "twenty-one million, three hundred sixty-five thousand, seven hundred fifty-nine".