636139997 has 2 divisors, whose sum is σ = 636139998. Its totient is φ = 636139996.

The previous prime is 636139991. The next prime is 636140039. The reversal of 636139997 is 799931636.

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., 629959801 + 6180196 = 25099^2 + 2486^2 .

It is a cyclic number.

It is not a de Polignac number, because 636139997 - 2⁴ = 636139981 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 (636139991) 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, 318069998 + 318069999.

It is an arithmetic number, because the mean of its divisors is an integer number (318069999).

Almost surely, 2^636139997 is an apocalyptic number.

It is an amenable number.

636139997 is a deficient number, since it is larger than the sum of its proper divisors (1).

636139997 is an equidigital number, since it uses as much as digits as its factorization.

636139997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1653372, while the sum is 53.

The square root of 636139997 is about 25221.8158941818. The cubic root of 636139997 is about 860.0378552834.

The spelling of 636139997 in words is "six hundred thirty-six million, one hundred thirty-nine thousand, nine hundred ninety-seven".