20859613 has 4 divisors (see below), whose sum is σ = 21578940. Its totient is φ = 20140288.

The previous prime is 20859589. The next prime is 20859617. The reversal of 20859613 is 31695802.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15578809 + 5280804 = 3947^2 + 2298^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20859613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20859617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359620 + ... + 359677.

It is an arithmetic number, because the mean of its divisors is an integer number (5394735).

Almost surely, 2^20859613 is an apocalyptic number.

It is an amenable number.

20859613 is a deficient number, since it is larger than the sum of its proper divisors (719327).

20859613 is an equidigital number, since it uses as much as digits as its factorization.

20859613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719326.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 20859613 is about 4567.2325318512. The cubic root of 20859613 is about 275.2762535238.

The spelling of 20859613 in words is "twenty million, eight hundred fifty-nine thousand, six hundred thirteen".