636149257 has 2 divisors, whose sum is σ = 636149258. Its totient is φ = 636149256.

The previous prime is 636149219. The next prime is 636149309. The reversal of 636149257 is 752941636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 509901561 + 126247696 = 22581^2 + 11236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636149257 is a prime.

It is not a weakly prime, because it can be changed into another prime (636149057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318074628 + 318074629.

It is an arithmetic number, because the mean of its divisors is an integer number (318074629).

Almost surely, 2^636149257 is an apocalyptic number.

It is an amenable number.

636149257 is a deficient number, since it is larger than the sum of its proper divisors (1).

636149257 is an equidigital number, since it uses as much as digits as its factorization.

636149257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 43.

The square root of 636149257 is about 25221.9994647530. Note that the first 3 decimals coincide. The cubic root of 636149257 is about 860.0420283228.

The spelling of 636149257 in words is "six hundred thirty-six million, one hundred forty-nine thousand, two hundred fifty-seven".