21313759 has 2 divisors, whose sum is σ = 21313760. Its totient is φ = 21313758.

The previous prime is 21313741. The next prime is 21313769. The reversal of 21313759 is 95731312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21313759 - 2⁹ = 21313247 is a prime.

It is equal to p_1348546 and since 21313759 and 1348546 have the same sum of digits, it is a Honaker prime.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 21313759.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21313729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656879 + 10656880.

It is an arithmetic number, because the mean of its divisors is an integer number (10656880).

Almost surely, 2^21313759 is an apocalyptic number.

21313759 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313759 is an equidigital number, since it uses as much as digits as its factorization.

21313759 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5670, while the sum is 31.

The square root of 21313759 is about 4616.6826834861. The cubic root of 21313759 is about 277.2596582538.

The spelling of 21313759 in words is "twenty-one million, three hundred thirteen thousand, seven hundred fifty-nine".