639477 has 12 divisors (see below), whose sum is σ = 946764. Its totient is φ = 415680.

The previous prime is 639451. The next prime is 639487. The reversal of 639477 is 774936.

It can be written as a sum of positive squares in 2 ways, for example, as 133956 + 505521 = 366^2 + 711^2 .

It is not a de Polignac number, because 639477 - 2¹⁰ = 638453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 498 + ... + 1235.

It is an arithmetic number, because the mean of its divisors is an integer number (78897).

2⁶³⁹⁴⁷⁷ is an apocalyptic number.

It is an amenable number.

639477 is a deficient number, since it is larger than the sum of its proper divisors (307287).

639477 is a wasteful number, since it uses less digits than its factorization.

639477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1780 (or 1777 counting only the distinct ones).

The product of its digits is 31752, while the sum is 36.

The square root of 639477 is about 799.6730581932. The cubic root of 639477 is about 86.1539068427.

The spelling of 639477 in words is "six hundred thirty-nine thousand, four hundred seventy-seven".