636761 has 2 divisors, whose sum is σ = 636762. Its totient is φ = 636760.

The previous prime is 636749. The next prime is 636763. The reversal of 636761 is 167636.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 534361 + 102400 = 731^2 + 320^2 .

It is a cyclic number.

It is not a de Polignac number, because 636761 - 2⁶ = 636697 is a prime.

It is a super-2 number, since 2×636761² = 810929142242, which contains 22 as substring.

Together with 636763, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (636763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318380 + 318381.

It is an arithmetic number, because the mean of its divisors is an integer number (318381).

2⁶³⁶⁷⁶¹ is an apocalyptic number.

It is an amenable number.

636761 is a deficient number, since it is larger than the sum of its proper divisors (1).

636761 is an equidigital number, since it uses as much as digits as its factorization.

636761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 29.

The square root of 636761 is about 797.9730571893. The cubic root of 636761 is about 86.0317621997.

The spelling of 636761 in words is "six hundred thirty-six thousand, seven hundred sixty-one".