20903613 has 8 divisors (see below), whose sum is σ = 28018176. Its totient is φ = 13862780.

The previous prime is 20903593. The next prime is 20903621. The reversal of 20903613 is 31630902.

It is an ABA number since it can be written as A⋅B^A, here for A=3, B=191.

It is not a de Polignac number, because 20903613 - 2⁶ = 20903549 is a prime.

It is a super-2 number, since 2×20903613² = 873922072907538, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20903683) 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, 109348 + ... + 109538.

It is an arithmetic number, because the mean of its divisors is an integer number (3502272).

Almost surely, 2^20903613 is an apocalyptic number.

It is an amenable number.

20903613 is a deficient number, since it is larger than the sum of its proper divisors (7114563).

20903613 is an frugal number, since it uses more digits than its factorization.

20903613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 24.

The square root of 20903613 is about 4572.0469157698. The cubic root of 20903613 is about 275.4696679287.

The spelling of 20903613 in words is "twenty million, nine hundred three thousand, six hundred thirteen".