21159613 has 2 divisors, whose sum is σ = 21159614. Its totient is φ = 21159612.

The previous prime is 21159587. The next prime is 21159617. The reversal of 21159613 is 31695112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20548089 + 611524 = 4533^2 + 782^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21159613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21159617) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579806 + 10579807.

It is an arithmetic number, because the mean of its divisors is an integer number (10579807).

Almost surely, 2^21159613 is an apocalyptic number.

It is an amenable number.

21159613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21159613 is an equidigital number, since it uses as much as digits as its factorization.

21159613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 28.

The square root of 21159613 is about 4599.9579345903. The cubic root of 21159613 is about 276.5896385617.

The spelling of 21159613 in words is "twenty-one million, one hundred fifty-nine thousand, six hundred thirteen".