20903997 has 4 divisors (see below), whose sum is σ = 27872000. Its totient is φ = 13935996.

The previous prime is 20903989. The next prime is 20904011. The reversal of 20903997 is 79930902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20903997 - 2³ = 20903989 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 (20903917) 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, 3483997 + ... + 3484002.

It is an arithmetic number, because the mean of its divisors is an integer number (6968000).

Almost surely, 2^20903997 is an apocalyptic number.

It is an amenable number.

20903997 is a deficient number, since it is larger than the sum of its proper divisors (6968003).

20903997 is an equidigital number, since it uses as much as digits as its factorization.

20903997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6968002.

The product of its (nonzero) digits is 30618, while the sum is 39.

The square root of 20903997 is about 4572.0889098967. The cubic root of 20903997 is about 275.4713547138.

The spelling of 20903997 in words is "twenty million, nine hundred three thousand, nine hundred ninety-seven".