625121309 has 2 divisors, whose sum is σ = 625121310. Its totient is φ = 625121308.

The previous prime is 625121279. The next prime is 625121333. The reversal of 625121309 is 903121526.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 414000409 + 211120900 = 20347^2 + 14530^2 .

It is a cyclic number.

It is not a de Polignac number, because 625121309 - 2⁸ = 625121053 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (625121339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312560654 + 312560655.

It is an arithmetic number, because the mean of its divisors is an integer number (312560655).

Almost surely, 2^625121309 is an apocalyptic number.

It is an amenable number.

625121309 is a deficient number, since it is larger than the sum of its proper divisors (1).

625121309 is an equidigital number, since it uses as much as digits as its factorization.

625121309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 625121309 is about 25002.4260622844. The cubic root of 625121309 is about 855.0432858858.

The spelling of 625121309 in words is "six hundred twenty-five million, one hundred twenty-one thousand, three hundred nine".