639787 has 8 divisors (see below), whose sum is σ = 680960. Its totient is φ = 599400.

The previous prime is 639757. The next prime is 639833. The reversal of 639787 is 787936.

639787 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 cyclic number.

It is not a de Polignac number, because 639787 - 2¹⁹ = 115499 is a prime.

It is a nialpdrome in base 15.

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 7 ways as a sum of consecutive naturals, for example, 2758 + ... + 2980.

It is an arithmetic number, because the mean of its divisors is an integer number (85120).

2⁶³⁹⁷⁸⁷ is an apocalyptic number.

639787 is a deficient number, since it is larger than the sum of its proper divisors (41173).

639787 is a wasteful number, since it uses less digits than its factorization.

639787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393.

The product of its digits is 63504, while the sum is 40.

The square root of 639787 is about 799.8668639217. The cubic root of 639787 is about 86.1678262365.

It can be divided in two parts, 6 and 39787, that added together give a palindrome (39793).

The spelling of 639787 in words is "six hundred thirty-nine thousand, seven hundred eighty-seven".