639252 has 30 divisors (see below), whose sum is σ = 1671978. Its totient is φ = 212976.

The previous prime is 639211. The next prime is 639253. The reversal of 639252 is 252936.

639252 is a `hidden beast` number, since 639 + 25 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 467856 + 171396 = 684^2 + 414^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639252.

It is not an unprimeable number, because it can be changed into a prime (639253) by changing a digit.

639252 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 in 9 ways as a sum of consecutive naturals, for example, 663 + ... + 1310.

2⁶³⁹²⁵² is an apocalyptic number.

It is an amenable number.

639252 is an abundant number, since it is smaller than the sum of its proper divisors (1032726).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639252 is a wasteful number, since it uses less digits than its factorization.

639252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989 (or 1978 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 639252 is about 799.5323633225. The cubic root of 639252 is about 86.1438012393.

It can be divided in two parts, 639 and 252, that multiplied together give a triangular number (161028 = T₅₆₇).

The spelling of 639252 in words is "six hundred thirty-nine thousand, two hundred fifty-two".