636641963 has 2 divisors, whose sum is σ = 636641964. Its totient is φ = 636641962.

The previous prime is 636641939. The next prime is 636642007. The reversal of 636641963 is 369146636.

It is an a-pointer prime, because the next prime (636642007) can be obtained adding 636641963 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 636641963 - 2¹² = 636637867 is a prime.

It is not a weakly prime, because it can be changed into another prime (636641063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318320981 + 318320982.

It is an arithmetic number, because the mean of its divisors is an integer number (318320982).

Almost surely, 2^636641963 is an apocalyptic number.

636641963 is a deficient number, since it is larger than the sum of its proper divisors (1).

636641963 is an equidigital number, since it uses as much as digits as its factorization.

636641963 is an evil number, because the sum of its binary digits is even.

The product of its digits is 419904, while the sum is 44.

The square root of 636641963 is about 25231.7649600657. The cubic root of 636641963 is about 860.2640089930.

The spelling of 636641963 in words is "six hundred thirty-six million, six hundred forty-one thousand, nine hundred sixty-three".