628639 has 4 divisors (see below), whose sum is σ = 685800. Its totient is φ = 571480.

The previous prime is 628591. The next prime is 628651. The reversal of 628639 is 936826.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 628639 - 2⁹ = 628127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (628679) 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 in 3 ways as a sum of consecutive naturals, for example, 28564 + ... + 28585.

It is an arithmetic number, because the mean of its divisors is an integer number (171450).

2⁶²⁸⁶³⁹ is an apocalyptic number.

628639 is a deficient number, since it is larger than the sum of its proper divisors (57161).

628639 is a wasteful number, since it uses less digits than its factorization.

628639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57160.

The product of its digits is 15552, while the sum is 34.

The square root of 628639 is about 792.8675803689. The cubic root of 628639 is about 85.6644123887.

The spelling of 628639 in words is "six hundred twenty-eight thousand, six hundred thirty-nine".