21903079 has 4 divisors (see below), whose sum is σ = 23894280. Its totient is φ = 19911880.

The previous prime is 21903073. The next prime is 21903083. The reversal of 21903079 is 97030912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21903079 - 2⁵ = 21903047 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21903079.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21903073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 995584 + ... + 995605.

It is an arithmetic number, because the mean of its divisors is an integer number (5973570).

Almost surely, 2^21903079 is an apocalyptic number.

21903079 is a deficient number, since it is larger than the sum of its proper divisors (1991201).

21903079 is a wasteful number, since it uses less digits than its factorization.

21903079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1991200.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 21903079 is about 4680.0725421728. The cubic root of 21903079 is about 279.7918478489.

The spelling of 21903079 in words is "twenty-one million, nine hundred three thousand, seventy-nine".