17797921 has 2 divisors, whose sum is σ = 17797922. Its totient is φ = 17797920.

The previous prime is 17797919. The next prime is 17797931. The reversal of 17797921 is 12979771.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16443025 + 1354896 = 4055^2 + 1164^2 .

It is a cyclic number.

It is not a de Polignac number, because 17797921 - 2¹ = 17797919 is a prime.

Together with 17797919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (17797931) 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 as a sum of consecutive naturals, namely, 8898960 + 8898961.

It is an arithmetic number, because the mean of its divisors is an integer number (8898961).

Almost surely, 2^17797921 is an apocalyptic number.

It is an amenable number.

17797921 is a deficient number, since it is larger than the sum of its proper divisors (1).

17797921 is an equidigital number, since it uses as much as digits as its factorization.

17797921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55566, while the sum is 43.

The square root of 17797921 is about 4218.7582296216. The cubic root of 17797921 is about 261.0897114330.

The spelling of 17797921 in words is "seventeen million, seven hundred ninety-seven thousand, nine hundred twenty-one".