628406509 has 2 divisors, whose sum is σ = 628406510. Its totient is φ = 628406508.

The previous prime is 628406501. The next prime is 628406561. The reversal of 628406509 is 905604826.

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., 435890884 + 192515625 = 20878^2 + 13875^2 .

It is a cyclic number.

It is not a de Polignac number, because 628406509 - 2³ = 628406501 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628406501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314203254 + 314203255.

It is an arithmetic number, because the mean of its divisors is an integer number (314203255).

Almost surely, 2^628406509 is an apocalyptic number.

It is an amenable number.

628406509 is a deficient number, since it is larger than the sum of its proper divisors (1).

628406509 is an equidigital number, since it uses as much as digits as its factorization.

628406509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 628406509 is about 25068.0375977060. The cubic root of 628406509 is about 856.5385059798.

The spelling of 628406509 in words is "six hundred twenty-eight million, four hundred six thousand, five hundred nine".