21608903 has 2 divisors, whose sum is σ = 21608904. Its totient is φ = 21608902.

The previous prime is 21608893. The next prime is 21608929. The reversal of 21608903 is 30980612.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21608903 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21608963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10804451 + 10804452.

It is an arithmetic number, because the mean of its divisors is an integer number (10804452).

Almost surely, 2^21608903 is an apocalyptic number.

21608903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21608903 is an equidigital number, since it uses as much as digits as its factorization.

21608903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21608903 is about 4648.5377270707. The cubic root of 21608903 is about 278.5335877844.

The spelling of 21608903 in words is "twenty-one million, six hundred eight thousand, nine hundred three".