21919903 has 2 divisors, whose sum is σ = 21919904. Its totient is φ = 21919902.

The previous prime is 21919847. The next prime is 21919927. The reversal of 21919903 is 30991912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21919903 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21919003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10959951 + 10959952.

It is an arithmetic number, because the mean of its divisors is an integer number (10959952).

Almost surely, 2^21919903 is an apocalyptic number.

21919903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21919903 is an equidigital number, since it uses as much as digits as its factorization.

21919903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 21919903 is about 4681.8696051898. The cubic root of 21919903 is about 279.8634665978.

It can be divided in two parts, 21919 and 903, that added together give a palindrome (22822).

The spelling of 21919903 in words is "twenty-one million, nine hundred nineteen thousand, nine hundred three".