171903989 has 2 divisors, whose sum is σ = 171903990. Its totient is φ = 171903988.

The previous prime is 171903943. The next prime is 171904043. The reversal of 171903989 is 989309171.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 169859089 + 2044900 = 13033^2 + 1430^2 .

It is an emirp because it is prime and its reverse (989309171) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 171903989 - 2⁸ = 171903733 is a prime.

It is a super-2 number, since 2×171903989² = 59101962868224242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (171903929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85951994 + 85951995.

It is an arithmetic number, because the mean of its divisors is an integer number (85951995).

Almost surely, 2^171903989 is an apocalyptic number.

It is an amenable number.

171903989 is a deficient number, since it is larger than the sum of its proper divisors (1).

171903989 is an equidigital number, since it uses as much as digits as its factorization.

171903989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 47.

The square root of 171903989 is about 13111.2161525924. The cubic root of 171903989 is about 556.0262795318.

The spelling of 171903989 in words is "one hundred seventy-one million, nine hundred three thousand, nine hundred eighty-nine".