21923903 has 2 divisors, whose sum is σ = 21923904. Its totient is φ = 21923902.

The previous prime is 21923833. The next prime is 21923911. The reversal of 21923903 is 30932912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21923903 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 (21923953) 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, 10961951 + 10961952.

It is an arithmetic number, because the mean of its divisors is an integer number (10961952).

Almost surely, 2^21923903 is an apocalyptic number.

21923903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21923903 is an equidigital number, since it uses as much as digits as its factorization.

21923903 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21923903 is about 4682.2967654774. The cubic root of 21923903 is about 279.8804889629.

Subtracting 21923903 from its reverse (30932912), we obtain a palindrome (9009009).

The spelling of 21923903 in words is "twenty-one million, nine hundred twenty-three thousand, nine hundred three".