21373903 has 2 divisors, whose sum is σ = 21373904. Its totient is φ = 21373902.

The previous prime is 21373897. The next prime is 21373927. The reversal of 21373903 is 30937312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21373903 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21373103) 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 as a sum of consecutive naturals, namely, 10686951 + 10686952.

It is an arithmetic number, because the mean of its divisors is an integer number (10686952).

Almost surely, 2^21373903 is an apocalyptic number.

21373903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21373903 is an equidigital number, since it uses as much as digits as its factorization.

21373903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3402, while the sum is 28.

The square root of 21373903 is about 4623.1918627719. The cubic root of 21373903 is about 277.5202073860.

The spelling of 21373903 in words is "twenty-one million, three hundred seventy-three thousand, nine hundred three".