636749 has 2 divisors, whose sum is σ = 636750. Its totient is φ = 636748.

The previous prime is 636739. The next prime is 636761. The reversal of 636749 is 947636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499849 + 136900 = 707^2 + 370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636749 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

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

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318374 + 318375.

It is an arithmetic number, because the mean of its divisors is an integer number (318375).

2⁶³⁶⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

636749 is a deficient number, since it is larger than the sum of its proper divisors (1).

636749 is an equidigital number, since it uses as much as digits as its factorization.

636749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 35.

The square root of 636749 is about 797.9655381030. The cubic root of 636749 is about 86.0312217627.

The spelling of 636749 in words is "six hundred thirty-six thousand, seven hundred forty-nine".