639898 has 8 divisors (see below), whose sum is σ = 1096992. Its totient is φ = 274236.

The previous prime is 639857. The next prime is 639907. The reversal of 639898 is 898936.

639898 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22840 + ... + 22867.

It is an arithmetic number, because the mean of its divisors is an integer number (137124).

2⁶³⁹⁸⁹⁸ is an apocalyptic number.

639898 is a deficient number, since it is larger than the sum of its proper divisors (457094).

639898 is a wasteful number, since it uses less digits than its factorization.

639898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45716.

The product of its digits is 93312, while the sum is 43.

The square root of 639898 is about 799.9362474598. The cubic root of 639898 is about 86.1728091843.

The spelling of 639898 in words is "six hundred thirty-nine thousand, eight hundred ninety-eight".