639494337 has 4 divisors (see below), whose sum is σ = 852659120. Its totient is φ = 426329556.

The previous prime is 639494311. The next prime is 639494351. The reversal of 639494337 is 733494936.

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 639494337 - 2⁷ = 639494209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639494357) 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, 106582387 + ... + 106582392.

It is an arithmetic number, because the mean of its divisors is an integer number (213164780).

Almost surely, 2^639494337 is an apocalyptic number.

It is an amenable number.

639494337 is a deficient number, since it is larger than the sum of its proper divisors (213164783).

639494337 is a wasteful number, since it uses less digits than its factorization.

639494337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213164782.

The product of its digits is 1469664, while the sum is 48.

The square root of 639494337 is about 25288.2252639445. The cubic root of 639494337 is about 861.5468541481.

It can be divided in two parts, 63949 and 4337, that added together give a palindrome (68286).

The spelling of 639494337 in words is "six hundred thirty-nine million, four hundred ninety-four thousand, three hundred thirty-seven".