639748 has 6 divisors (see below), whose sum is σ = 1119566. Its totient is φ = 319872.

The previous prime is 639739. The next prime is 639757. The reversal of 639748 is 847936.

It is an interprime number because it is at equal distance from previous prime (639739) and next prime (639757).

It can be written as a sum of positive squares in only one way, i.e., 611524 + 28224 = 782^2 + 168^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79965 + ... + 79972.

2⁶³⁹⁷⁴⁸ is an apocalyptic number.

It is an amenable number.

639748 is a deficient number, since it is larger than the sum of its proper divisors (479818).

639748 is a wasteful number, since it uses less digits than its factorization.

639748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159941 (or 159939 counting only the distinct ones).

The product of its digits is 36288, while the sum is 37.

The square root of 639748 is about 799.8424844930. The cubic root of 639748 is about 86.1660753343.

The spelling of 639748 in words is "six hundred thirty-nine thousand, seven hundred forty-eight".