168210257 has 4 divisors (see below), whose sum is σ = 178104996. Its totient is φ = 158315520.

The previous prime is 168210241. The next prime is 168210299. The reversal of 168210257 is 752012861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 752012861 = 313 ⋅2402597.

It can be written as a sum of positive squares in 2 ways, for example, as 136445761 + 31764496 = 11681^2 + 5636^2 .

It is a cyclic number.

It is not a de Polignac number, because 168210257 - 2⁴ = 168210241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168210457) 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 in 3 ways as a sum of consecutive naturals, for example, 4947344 + ... + 4947377.

It is an arithmetic number, because the mean of its divisors is an integer number (44526249).

Almost surely, 2^168210257 is an apocalyptic number.

168210257 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

168210257 is a deficient number, since it is larger than the sum of its proper divisors (9894739).

168210257 is an equidigital number, since it uses as much as digits as its factorization.

168210257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9894738.

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 168210257 is about 12969.5897005264. The cubic root of 168210257 is about 552.0149310268.

The spelling of 168210257 in words is "one hundred sixty-eight million, two hundred ten thousand, two hundred fifty-seven".