17720231 has 2 divisors, whose sum is σ = 17720232. Its totient is φ = 17720230.

The previous prime is 17720221. The next prime is 17720233. The reversal of 17720231 is 13202771.

It is a strong prime.

It is an emirp because it is prime and its reverse (13202771) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-17720231 is a prime.

It is a super-2 number, since 2×17720231² = 628013173386722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 17720233, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 17720197 and 17720206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17720233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8860115 + 8860116.

It is an arithmetic number, because the mean of its divisors is an integer number (8860116).

Almost surely, 2^17720231 is an apocalyptic number.

17720231 is a deficient number, since it is larger than the sum of its proper divisors (1).

17720231 is an equidigital number, since it uses as much as digits as its factorization.

17720231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 17720231 is about 4209.5404737334. The cubic root of 17720231 is about 260.7092616498.

The spelling of 17720231 in words is "seventeen million, seven hundred twenty thousand, two hundred thirty-one".