639522 has 32 divisors (see below), whose sum is σ = 1532160. Its totient is φ = 196560.

The previous prime is 639517. The next prime is 639533. The reversal of 639522 is 225936.

639522 is a `hidden beast` number, since 639 + 5 + 22 = 666.

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

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 in 15 ways as a sum of consecutive naturals, for example, 247 + ... + 1157.

It is an arithmetic number, because the mean of its divisors is an integer number (47880).

2⁶³⁹⁵²² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (766080).

639522 is an abundant number, since it is smaller than the sum of its proper divisors (892638).

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

639522 is a wasteful number, since it uses less digits than its factorization.

639522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935 (or 929 counting only the distinct ones).

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

The square root of 639522 is about 799.7011941969. The cubic root of 639522 is about 86.1559276790.

The spelling of 639522 in words is "six hundred thirty-nine thousand, five hundred twenty-two".