21793617 has 10 divisors (see below), whose sum is σ = 32556018. Its totient is φ = 14529024.

The previous prime is 21793613. The next prime is 21793619. The reversal of 21793617 is 71639712.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15397776 + 6395841 = 3924^2 + 2529^2 .

It is not a de Polignac number, because 21793617 - 2² = 21793613 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21793613) by changing a digit.

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 9 ways as a sum of consecutive naturals, for example, 134448 + ... + 134609.

Almost surely, 2^21793617 is an apocalyptic number.

21793617 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21793617 is a deficient number, since it is larger than the sum of its proper divisors (10762401).

21793617 is an equidigital number, since it uses as much as digits as its factorization.

21793617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269069 (or 269060 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21793617 is about 4668.3634177300. The cubic root of 21793617 is about 279.3249768552.

The spelling of 21793617 in words is "twenty-one million, seven hundred ninety-three thousand, six hundred seventeen".