21990713 has 2 divisors, whose sum is σ = 21990714. Its totient is φ = 21990712.

The previous prime is 21990701. The next prime is 21990721. The reversal of 21990713 is 31709912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14417209 + 7573504 = 3797^2 + 2752^2 .

It is a cyclic number.

It is not a de Polignac number, because 21990713 - 2⁴ = 21990697 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21990713.

It is not a weakly prime, because it can be changed into another prime (21990013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10995356 + 10995357.

It is an arithmetic number, because the mean of its divisors is an integer number (10995357).

Almost surely, 2^21990713 is an apocalyptic number.

It is an amenable number.

21990713 is a deficient number, since it is larger than the sum of its proper divisors (1).

21990713 is an equidigital number, since it uses as much as digits as its factorization.

21990713 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21990713 is about 4689.4256577965. The cubic root of 21990713 is about 280.1644994264.

The spelling of 21990713 in words is "twenty-one million, nine hundred ninety thousand, seven hundred thirteen".