625688909 has 2 divisors, whose sum is σ = 625688910. Its totient is φ = 625688908.

The previous prime is 625688887. The next prime is 625688939. The reversal of 625688909 is 909886526.

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., 352613284 + 273075625 = 18778^2 + 16525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-625688909 is a prime.

It is a super-2 number, since 2×625688909² = 782973221691220562, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (625688939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312844454 + 312844455.

It is an arithmetic number, because the mean of its divisors is an integer number (312844455).

Almost surely, 2^625688909 is an apocalyptic number.

It is an amenable number.

625688909 is a deficient number, since it is larger than the sum of its proper divisors (1).

625688909 is an equidigital number, since it uses as much as digits as its factorization.

625688909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1866240, while the sum is 53.

The square root of 625688909 is about 25013.7743853262. The cubic root of 625688909 is about 855.3019960741.

The spelling of 625688909 in words is "six hundred twenty-five million, six hundred eighty-eight thousand, nine hundred nine".