21793117 has 2 divisors, whose sum is σ = 21793118. Its totient is φ = 21793116.

The previous prime is 21793097. The next prime is 21793127. The reversal of 21793117 is 71139712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16475481 + 5317636 = 4059^2 + 2306^2 .

It is a cyclic number.

It is not a de Polignac number, because 21793117 - 2⁷ = 21792989 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21793127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10896558 + 10896559.

It is an arithmetic number, because the mean of its divisors is an integer number (10896559).

Almost surely, 2^21793117 is an apocalyptic number.

It is an amenable number.

21793117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21793117 is an equidigital number, since it uses as much as digits as its factorization.

21793117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2646, while the sum is 31.

The square root of 21793117 is about 4668.3098654652. The cubic root of 21793117 is about 279.3228407013.

The spelling of 21793117 in words is "twenty-one million, seven hundred ninety-three thousand, one hundred seventeen".