639681552 has 30 divisors (see below), whose sum is σ = 1790220302. Its totient is φ = 213227136.

The previous prime is 639681551. The next prime is 639681577. The reversal of 639681552 is 255186936.

639681552 is a `hidden beast` number, since 6 + 3 + 96 + 8 + 1 + 552 = 666.

It can be written as a sum of positive squares in only one way, i.e., 615238416 + 24443136 = 24804^2 + 4944^2 .

It is a junction number, because it is equal to n+sod(n) for n = 639681498 and 639681507.

It is not an unprimeable number, because it can be changed into a prime (639681551) 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, 2220973 + ... + 2221260.

Almost surely, 2^639681552 is an apocalyptic number.

It is an amenable number.

639681552 is an abundant number, since it is smaller than the sum of its proper divisors (1150538750).

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

639681552 is a wasteful number, since it uses less digits than its factorization.

639681552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4442247 (or 4442238 counting only the distinct ones).

The product of its digits is 388800, while the sum is 45.

The square root of 639681552 is about 25291.9266170057. The cubic root of 639681552 is about 861.6309199209.

The spelling of 639681552 in words is "six hundred thirty-nine million, six hundred eighty-one thousand, five hundred fifty-two".