21903745 has 8 divisors (see below), whose sum is σ = 26461800. Its totient is φ = 17404800.

The previous prime is 21903737. The next prime is 21903779. The reversal of 21903745 is 54730912.

It can be written as a sum of positive squares in 4 ways, for example, as 309136 + 21594609 = 556^2 + 4647^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21903745 - 2³ = 21903737 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13956 + ... + 15445.

It is an arithmetic number, because the mean of its divisors is an integer number (3307725).

Almost surely, 2^21903745 is an apocalyptic number.

It is an amenable number.

21903745 is a deficient number, since it is larger than the sum of its proper divisors (4558055).

21903745 is a wasteful number, since it uses less digits than its factorization.

21903745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29555.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21903745 is about 4680.1436943752. The cubic root of 21903745 is about 279.7946836676.

The spelling of 21903745 in words is "twenty-one million, nine hundred three thousand, seven hundred forty-five".