636746857 has 2 divisors, whose sum is σ = 636746858. Its totient is φ = 636746856.

The previous prime is 636746833. The next prime is 636746893. The reversal of 636746857 is 758647636.

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., 353026521 + 283720336 = 18789^2 + 16844^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636746857 is a prime.

It is not a weakly prime, because it can be changed into another prime (636746657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318373428 + 318373429.

It is an arithmetic number, because the mean of its divisors is an integer number (318373429).

Almost surely, 2^636746857 is an apocalyptic number.

It is an amenable number.

636746857 is a deficient number, since it is larger than the sum of its proper divisors (1).

636746857 is an equidigital number, since it uses as much as digits as its factorization.

636746857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5080320, while the sum is 52.

The square root of 636746857 is about 25233.8434844952. The cubic root of 636746857 is about 860.3112524898.

The spelling of 636746857 in words is "six hundred thirty-six million, seven hundred forty-six thousand, eight hundred fifty-seven".