20993903 has 12 divisors (see below), whose sum is σ = 24555600. Its totient is φ = 17896032.

The previous prime is 20993897. The next prime is 20993923. The reversal of 20993903 is 30939902.

It is not a de Polignac number, because 20993903 - 2⁶ = 20993839 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 (20993923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8675 + ... + 10827.

It is an arithmetic number, because the mean of its divisors is an integer number (2046300).

Almost surely, 2^20993903 is an apocalyptic number.

20993903 is a deficient number, since it is larger than the sum of its proper divisors (3561697).

20993903 is a wasteful number, since it uses less digits than its factorization.

20993903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2366 (or 2359 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 35.

The square root of 20993903 is about 4581.9104094253. The cubic root of 20993903 is about 275.8657147986.

The spelling of 20993903 in words is "twenty million, nine hundred ninety-three thousand, nine hundred three".