634440509 has 2 divisors, whose sum is σ = 634440510. Its totient is φ = 634440508.

The previous prime is 634440503. The next prime is 634440553. The reversal of 634440509 is 905044436.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 516652900 + 117787609 = 22730^2 + 10853^2 .

It is a cyclic number.

It is not a de Polignac number, because 634440509 - 2⁸ = 634440253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (634440503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317220254 + 317220255.

It is an arithmetic number, because the mean of its divisors is an integer number (317220255).

Almost surely, 2^634440509 is an apocalyptic number.

It is an amenable number.

634440509 is a deficient number, since it is larger than the sum of its proper divisors (1).

634440509 is an equidigital number, since it uses as much as digits as its factorization.

634440509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 634440509 is about 25188.1025287734. The cubic root of 634440509 is about 859.2712905001.

The spelling of 634440509 in words is "six hundred thirty-four million, four hundred forty thousand, five hundred nine".