20913903 has 8 divisors (see below), whose sum is σ = 30983600. Its totient is φ = 13942584.

The previous prime is 20913887. The next prime is 20913931. The reversal of 20913903 is 30931902.

It is not a de Polignac number, because 20913903 - 2⁴ = 20913887 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: 774589 = 20913903 / (2 + 0 + 9 + 1 + 3 + 9 + 0 + 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 (20913203) 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, 387268 + ... + 387321.

It is an arithmetic number, because the mean of its divisors is an integer number (3872950).

Almost surely, 2^20913903 is an apocalyptic number.

20913903 is a deficient number, since it is larger than the sum of its proper divisors (10069697).

20913903 is an equidigital number, since it uses as much as digits as its factorization.

20913903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 774598 (or 774592 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 20913903 is about 4573.1720938535. The cubic root of 20913903 is about 275.5148613584.

The spelling of 20913903 in words is "twenty million, nine hundred thirteen thousand, nine hundred three".