21791073 has 8 divisors (see below), whose sum is σ = 29107936. Its totient is φ = 14500800.

The previous prime is 21791057. The next prime is 21791087. The reversal of 21791073 is 37019712.

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

It is not a de Polignac number, because 21791073 - 2⁴ = 21791057 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 21791073.

It is not an unprimeable number, because it can be changed into a prime (21791023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4648 + ... + 8073.

It is an arithmetic number, because the mean of its divisors is an integer number (3638492).

Almost surely, 2^21791073 is an apocalyptic number.

It is an amenable number.

21791073 is a deficient number, since it is larger than the sum of its proper divisors (7316863).

21791073 is a wasteful number, since it uses less digits than its factorization.

21791073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13295.

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 21791073 is about 4668.0909374176. The cubic root of 21791073 is about 279.3141077646.

The spelling of 21791073 in words is "twenty-one million, seven hundred ninety-one thousand, seventy-three".