639694 has 8 divisors (see below), whose sum is σ = 1046808. Its totient is φ = 290760.

The previous prime is 639689. The next prime is 639697. The reversal of 639694 is 496936.

639694 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 not an unprimeable number, because it can be changed into a prime (639697) 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, 14517 + ... + 14560.

It is an arithmetic number, because the mean of its divisors is an integer number (130851).

2⁶³⁹⁶⁹⁴ is an apocalyptic number.

639694 is a deficient number, since it is larger than the sum of its proper divisors (407114).

639694 is a wasteful number, since it uses less digits than its factorization.

639694 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29090.

The product of its digits is 34992, while the sum is 37.

The square root of 639694 is about 799.8087271342. The cubic root of 639694 is about 86.1636508906.

The spelling of 639694 in words is "six hundred thirty-nine thousand, six hundred ninety-four".