21360817 has 2 divisors, whose sum is σ = 21360818. Its totient is φ = 21360816.

The previous prime is 21360811. The next prime is 21360827. The reversal of 21360817 is 71806312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21307456 + 53361 = 4616^2 + 231^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21360817 is a prime.

It is not a weakly prime, because it can be changed into another prime (21360811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10680408 + 10680409.

It is an arithmetic number, because the mean of its divisors is an integer number (10680409).

Almost surely, 2^21360817 is an apocalyptic number.

It is an amenable number.

21360817 is a deficient number, since it is larger than the sum of its proper divisors (1).

21360817 is an equidigital number, since it uses as much as digits as its factorization.

21360817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21360817 is about 4621.7763900907. The cubic root of 21360817 is about 277.4635593195.

The spelling of 21360817 in words is "twenty-one million, three hundred sixty thousand, eight hundred seventeen".