21293903 has 2 divisors, whose sum is σ = 21293904. Its totient is φ = 21293902.

The previous prime is 21293887. The next prime is 21293939. The reversal of 21293903 is 30939212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21293903 - 2⁴ = 21293887 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 (21293953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646951 + 10646952.

It is an arithmetic number, because the mean of its divisors is an integer number (10646952).

Almost surely, 2^21293903 is an apocalyptic number.

21293903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293903 is an equidigital number, since it uses as much as digits as its factorization.

21293903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 21293903 is about 4614.5317205541. The cubic root of 21293903 is about 277.1735326946.

The spelling of 21293903 in words is "twenty-one million, two hundred ninety-three thousand, nine hundred three".