21903453 has 80 divisors (see below), whose sum is σ = 40330752. Its totient is φ = 11664000.

The previous prime is 21903449. The next prime is 21903487. The reversal of 21903453 is 35430912.

It is not a de Polignac number, because 21903453 - 2² = 21903449 is a prime.

It is a super-2 number, since 2×21903453² = 959522506646418, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21903403) 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 in 79 ways as a sum of consecutive naturals, for example, 359043 + ... + 359103.

Almost surely, 2^21903453 is an apocalyptic number.

It is an amenable number.

21903453 is a deficient number, since it is larger than the sum of its proper divisors (18427299).

21903453 is a wasteful number, since it uses less digits than its factorization.

21903453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21903453 is about 4680.1124986479. The cubic root of 21903453 is about 279.7934403428.

The spelling of 21903453 in words is "twenty-one million, nine hundred three thousand, four hundred fifty-three".