636124081 has 2 divisors, whose sum is σ = 636124082. Its totient is φ = 636124080.

The previous prime is 636124039. The next prime is 636124127. The reversal of 636124081 is 180421636.

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., 634586481 + 1537600 = 25191^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 636124081 - 2⁷ = 636123953 is a prime.

It is a super-2 number, since 2×636124081² = 809307692856189122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (636124001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318062040 + 318062041.

It is an arithmetic number, because the mean of its divisors is an integer number (318062041).

Almost surely, 2^636124081 is an apocalyptic number.

It is an amenable number.

636124081 is a deficient number, since it is larger than the sum of its proper divisors (1).

636124081 is an equidigital number, since it uses as much as digits as its factorization.

636124081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 636124081 is about 25221.5003717067. The cubic root of 636124081 is about 860.0306826082.

The spelling of 636124081 in words is "six hundred thirty-six million, one hundred twenty-four thousand, eighty-one".