17491921 has 2 divisors, whose sum is σ = 17491922. Its totient is φ = 17491920.

The previous prime is 17491909. The next prime is 17491931. The reversal of 17491921 is 12919471.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10653696 + 6838225 = 3264^2 + 2615^2 .

It is a cyclic number.

It is not a de Polignac number, because 17491921 - 2⁵ = 17491889 is a prime.

It is not a weakly prime, because it can be changed into another prime (17491931) 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, 8745960 + 8745961.

It is an arithmetic number, because the mean of its divisors is an integer number (8745961).

Almost surely, 2^17491921 is an apocalyptic number.

It is an amenable number.

17491921 is a deficient number, since it is larger than the sum of its proper divisors (1).

17491921 is an equidigital number, since it uses as much as digits as its factorization.

17491921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 34.

The square root of 17491921 is about 4182.3343960042. The cubic root of 17491921 is about 259.5847464097.

The spelling of 17491921 in words is "seventeen million, four hundred ninety-one thousand, nine hundred twenty-one".