620666909 has 2 divisors, whose sum is σ = 620666910. Its totient is φ = 620666908.

The previous prime is 620666873. The next prime is 620666929. The reversal of 620666909 is 909666026.

It is a happy number.

620666909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 578546809 + 42120100 = 24053^2 + 6490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-620666909 is a prime.

It is a super-2 number, since 2×620666909² = 770454823855228562, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 620666909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620666929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310333454 + 310333455.

It is an arithmetic number, because the mean of its divisors is an integer number (310333455).

Almost surely, 2^620666909 is an apocalyptic number.

It is an amenable number.

620666909 is a deficient number, since it is larger than the sum of its proper divisors (1).

620666909 is an equidigital number, since it uses as much as digits as its factorization.

620666909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 620666909 is about 24913.1874516289. The cubic root of 620666909 is about 853.0075277862.

The spelling of 620666909 in words is "six hundred twenty million, six hundred sixty-six thousand, nine hundred nine".