21607613 has 2 divisors, whose sum is σ = 21607614. Its totient is φ = 21607612.

The previous prime is 21607591. The next prime is 21607633. The reversal of 21607613 is 31670612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14915044 + 6692569 = 3862^2 + 2587^2 .

It is a cyclic number.

It is not a de Polignac number, because 21607613 - 2⁶ = 21607549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21607633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10803806 + 10803807.

It is an arithmetic number, because the mean of its divisors is an integer number (10803807).

Almost surely, 2^21607613 is an apocalyptic number.

It is an amenable number.

21607613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21607613 is an equidigital number, since it uses as much as digits as its factorization.

21607613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21607613 is about 4648.3989716891. The cubic root of 21607613 is about 278.5280450771.

The spelling of 21607613 in words is "twenty-one million, six hundred seven thousand, six hundred thirteen".