639345682 has 4 divisors (see below), whose sum is σ = 959018526. Its totient is φ = 319672840.

The previous prime is 639345667. The next prime is 639345703. The reversal of 639345682 is 286543936.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 631567161 + 7778521 = 25131^2 + 2789^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159836419 + ... + 159836422.

Almost surely, 2^639345682 is an apocalyptic number.

639345682 is a deficient number, since it is larger than the sum of its proper divisors (319672844).

639345682 is a wasteful number, since it uses less digits than its factorization.

639345682 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319672843.

The product of its digits is 933120, while the sum is 46.

The square root of 639345682 is about 25285.2858793410. The cubic root of 639345682 is about 861.4800914131.

The spelling of 639345682 in words is "six hundred thirty-nine million, three hundred forty-five thousand, six hundred eighty-two".