21903573 has 16 divisors (see below), whose sum is σ = 30159360. Its totient is φ = 14132976.

The previous prime is 21903569. The next prime is 21903587. The reversal of 21903573 is 37530912.

It is not a de Polignac number, because 21903573 - 2² = 21903569 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21903573.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21903533) 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 15 ways as a sum of consecutive naturals, for example, 10936 + ... + 12782.

It is an arithmetic number, because the mean of its divisors is an integer number (1884960).

Almost surely, 2^21903573 is an apocalyptic number.

It is an amenable number.

21903573 is a deficient number, since it is larger than the sum of its proper divisors (8255787).

21903573 is a wasteful number, since it uses less digits than its factorization.

21903573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1976.

The product of its (nonzero) digits is 5670, while the sum is 30.

The square root of 21903573 is about 4680.1253188350. The cubic root of 21903573 is about 279.7939512995.

The spelling of 21903573 in words is "twenty-one million, nine hundred three thousand, five hundred seventy-three".