639228 has 12 divisors (see below), whose sum is σ = 1491560. Its totient is φ = 213072.

The previous prime is 639211. The next prime is 639253. The reversal of 639228 is 822936.

639228 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×639228² = 817224871968, which contains 22 as substring.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a d-powerful number, because it can be written as 6⁵ + 3¹² + 2 + 9⁵ + 2¹³ + 8⁵ .

It is a junction number, because it is equal to n+sod(n) for n = 639195 and 639204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26623 + ... + 26646.

2⁶³⁹²²⁸ is an apocalyptic number.

It is an amenable number.

639228 is an abundant number, since it is smaller than the sum of its proper divisors (852332).

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

639228 is a wasteful number, since it uses less digits than its factorization.

639228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53276 (or 53274 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 639228 is about 799.5173544083. The cubic root of 639228 is about 86.1427231683.

The spelling of 639228 in words is "six hundred thirty-nine thousand, two hundred twenty-eight".