646164257 has 2 divisors, whose sum is σ = 646164258. Its totient is φ = 646164256.

The previous prime is 646164227. The next prime is 646164289. The reversal of 646164257 is 752461646.

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., 542144656 + 104019601 = 23284^2 + 10199^2 .

It is a cyclic number.

It is not a de Polignac number, because 646164257 - 2¹⁰ = 646163233 is a prime.

It is not a weakly prime, because it can be changed into another prime (646164227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323082128 + 323082129.

It is an arithmetic number, because the mean of its divisors is an integer number (323082129).

Almost surely, 2^646164257 is an apocalyptic number.

It is an amenable number.

646164257 is a deficient number, since it is larger than the sum of its proper divisors (1).

646164257 is an equidigital number, since it uses as much as digits as its factorization.

646164257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 41.

The square root of 646164257 is about 25419.7611515136. The cubic root of 646164257 is about 864.5318089573.

The spelling of 646164257 in words is "six hundred forty-six million, one hundred sixty-four thousand, two hundred fifty-seven".