20663613 has 8 divisors (see below), whose sum is σ = 30612800. Its totient is φ = 13775724.

The previous prime is 20663611. The next prime is 20663623. The reversal of 20663613 is 31636602.

20663613 is a `hidden beast` number, since 20 + 6 + 636 + 1 + 3 = 666.

It is not a de Polignac number, because 20663613 - 2¹ = 20663611 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 765319 = 20663613 / (2 + 0 + 6 + 6 + 3 + 6 + 1 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20663611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 382633 + ... + 382686.

It is an arithmetic number, because the mean of its divisors is an integer number (3826600).

Almost surely, 2^20663613 is an apocalyptic number.

It is an amenable number.

20663613 is a deficient number, since it is larger than the sum of its proper divisors (9949187).

20663613 is an equidigital number, since it uses as much as digits as its factorization.

20663613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765328 (or 765322 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

The square root of 20663613 is about 4545.7246946994. The cubic root of 20663613 is about 274.4113601943.

The spelling of 20663613 in words is "twenty million, six hundred sixty-three thousand, six hundred thirteen".