21965413 has 2 divisors, whose sum is σ = 21965414. Its totient is φ = 21965412.

The previous prime is 21965371. The next prime is 21965417. The reversal of 21965413 is 31456912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17156164 + 4809249 = 4142^2 + 2193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21965413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21965417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10982706 + 10982707.

It is an arithmetic number, because the mean of its divisors is an integer number (10982707).

Almost surely, 2^21965413 is an apocalyptic number.

It is an amenable number.

21965413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21965413 is an equidigital number, since it uses as much as digits as its factorization.

21965413 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 21965413 is about 4686.7273229835. The cubic root of 21965413 is about 280.0570164502.

The spelling of 21965413 in words is "twenty-one million, nine hundred sixty-five thousand, four hundred thirteen".