639797 has 4 divisors (see below), whose sum is σ = 654720. Its totient is φ = 624876.

The previous prime is 639757. The next prime is 639833. The reversal of 639797 is 797936.

639797 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 639797 - 2¹⁶ = 574261 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 3⁵ + 7 + 9⁵ + 9⁶ + 7⁴ .

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639757) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7397 + ... + 7482.

It is an arithmetic number, because the mean of its divisors is an integer number (163680).

2⁶³⁹⁷⁹⁷ is an apocalyptic number.

It is an amenable number.

639797 is a deficient number, since it is larger than the sum of its proper divisors (14923).

639797 is a wasteful number, since it uses less digits than its factorization.

639797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14922.

The product of its digits is 71442, while the sum is 41.

The square root of 639797 is about 799.8731149376. The cubic root of 639797 is about 86.1682751744.

The spelling of 639797 in words is "six hundred thirty-nine thousand, seven hundred ninety-seven".