998171957 has 2 divisors, whose sum is σ = 998171958. Its totient is φ = 998171956.

The previous prime is 998171899. The next prime is 998171987. The reversal of 998171957 is 759171899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 606686161 + 391485796 = 24631^2 + 19786^2 .

It is a cyclic number.

It is not a de Polignac number, because 998171957 - 2¹⁰ = 998170933 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 (998171987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499085978 + 499085979.

It is an arithmetic number, because the mean of its divisors is an integer number (499085979).

Almost surely, 2^998171957 is an apocalyptic number.

It is an amenable number.

998171957 is a deficient number, since it is larger than the sum of its proper divisors (1).

998171957 is an equidigital number, since it uses as much as digits as its factorization.

998171957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1428840, while the sum is 56.

The square root of 998171957 is about 31593.8594825007. The cubic root of 998171957 is about 999.3902806512.

It can be divided in two parts, 9981 and 71957, that multiplied together give a palindrome (718202817).

The spelling of 998171957 in words is "nine hundred ninety-eight million, one hundred seventy-one thousand, nine hundred fifty-seven".