628909857 has 6 divisors (see below), whose sum is σ = 908425362. Its totient is φ = 419273232.

The previous prime is 628909837. The next prime is 628909901. The reversal of 628909857 is 758909826.

It is a happy number.

628909857 is a `hidden beast` number, since 628 + 9 + 0 + 9 + 8 + 5 + 7 = 666.

628909857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 572118561 + 56791296 = 23919^2 + 7536^2 .

It is not a de Polignac number, because 628909857 - 2⁸ = 628909601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (628909807) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34939428 + ... + 34939445.

It is an arithmetic number, because the mean of its divisors is an integer number (151404227).

Almost surely, 2^628909857 is an apocalyptic number.

It is an amenable number.

628909857 is a deficient number, since it is larger than the sum of its proper divisors (279515505).

628909857 is a wasteful number, since it uses less digits than its factorization.

628909857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69878879 (or 69878876 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The square root of 628909857 is about 25078.0752251842. The cubic root of 628909857 is about 856.7671381771.

The spelling of 628909857 in words is "six hundred twenty-eight million, nine hundred nine thousand, eight hundred fifty-seven".