21715745459 has 2 divisors, whose sum is σ = 21715745460. Its totient is φ = 21715745458.

The previous prime is 21715745437. The next prime is 21715745521. The reversal of 21715745459 is 95454751712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21715745459 is a prime.

It is not a weakly prime, because it can be changed into another prime (21715745059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10857872729 + 10857872730.

It is an arithmetic number, because the mean of its divisors is an integer number (10857872730).

Almost surely, 2^21715745459 is an apocalyptic number.

21715745459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21715745459 is an equidigital number, since it uses as much as digits as its factorization.

21715745459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1764000, while the sum is 50.

The spelling of 21715745459 in words is "twenty-one billion, seven hundred fifteen million, seven hundred forty-five thousand, four hundred fifty-nine".