639957834 has 40 divisors (see below), whose sum is σ = 1435563360. Its totient is φ = 213083784.

The previous prime is 639957833. The next prime is 639957841. The reversal of 639957834 is 438759936.

639957834 is a `hidden beast` number, since 6 + 39 + 9 + 578 + 34 = 666.

639957834 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (639957833) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 206307 + ... + 209385.

It is an arithmetic number, because the mean of its divisors is an integer number (35889084).

Almost surely, 2^639957834 is an apocalyptic number.

639957834 is an abundant number, since it is smaller than the sum of its proper divisors (795605526).

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

639957834 is a wasteful number, since it uses less digits than its factorization.

639957834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4376 (or 4367 counting only the distinct ones).

The product of its digits is 4898880, while the sum is 54.

The square root of 639957834 is about 25297.3878888711. The cubic root of 639957834 is about 861.7549497860.

The spelling of 639957834 in words is "six hundred thirty-nine million, nine hundred fifty-seven thousand, eight hundred thirty-four".