21696413 has 2 divisors, whose sum is σ = 21696414. Its totient is φ = 21696412.

The previous prime is 21696401. The next prime is 21696427. The reversal of 21696413 is 31469612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14417209 + 7279204 = 3797^2 + 2698^2 .

It is a cyclic number.

It is not a de Polignac number, because 21696413 - 2⁶ = 21696349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21696413.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21696443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10848206 + 10848207.

It is an arithmetic number, because the mean of its divisors is an integer number (10848207).

Almost surely, 2^21696413 is an apocalyptic number.

It is an amenable number.

21696413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21696413 is an equidigital number, since it uses as much as digits as its factorization.

21696413 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 21696413 is about 4657.9408540685. The cubic root of 21696413 is about 278.9090756845.

The spelling of 21696413 in words is "twenty-one million, six hundred ninety-six thousand, four hundred thirteen".