636123643 has 2 divisors, whose sum is σ = 636123644. Its totient is φ = 636123642.

The previous prime is 636123641. The next prime is 636123701. The reversal of 636123643 is 346321636.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 636123643 - 2¹ = 636123641 is a prime.

Together with 636123641, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 636123599 and 636123608.

It is not a weakly prime, because it can be changed into another prime (636123641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318061821 + 318061822.

It is an arithmetic number, because the mean of its divisors is an integer number (318061822).

Almost surely, 2^636123643 is an apocalyptic number.

636123643 is a deficient number, since it is larger than the sum of its proper divisors (1).

636123643 is an equidigital number, since it uses as much as digits as its factorization.

636123643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 34.

The square root of 636123643 is about 25221.4916886373. The cubic root of 636123643 is about 860.0304852182.

The spelling of 636123643 in words is "six hundred thirty-six million, one hundred twenty-three thousand, six hundred forty-three".