639754 has 12 divisors (see below), whose sum is σ = 988146. Its totient is φ = 310632.

The previous prime is 639739. The next prime is 639757. The reversal of 639754 is 457936.

It can be written as a sum of positive squares in only one way, i.e., 416025 + 223729 = 645^2 + 473^2 .

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 5 ways as a sum of consecutive naturals, for example, 3612 + ... + 3784.

2⁶³⁹⁷⁵⁴ is an apocalyptic number.

639754 is a deficient number, since it is larger than the sum of its proper divisors (348392).

639754 is a wasteful number, since it uses less digits than its factorization.

639754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 218 counting only the distinct ones).

The product of its digits is 22680, while the sum is 34.

The square root of 639754 is about 799.8462352227. The cubic root of 639754 is about 86.1663447085.

The spelling of 639754 in words is "six hundred thirty-nine thousand, seven hundred fifty-four".