640834742 has 16 divisors (see below), whose sum is σ = 967963392. Its totient is φ = 318188520.

The previous prime is 640834739. The next prime is 640834757. The reversal of 640834742 is 247438046.

640834742 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 640834696 and 640834705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180767 + ... + 184277.

It is an arithmetic number, because the mean of its divisors is an integer number (60497712).

Almost surely, 2^640834742 is an apocalyptic number.

640834742 is a deficient number, since it is larger than the sum of its proper divisors (327128650).

640834742 is a wasteful number, since it uses less digits than its factorization.

640834742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4123.

The product of its (nonzero) digits is 129024, while the sum is 38.

The square root of 640834742 is about 25314.7139426856. The cubic root of 640834742 is about 862.1483793074.

The spelling of 640834742 in words is "six hundred forty million, eight hundred thirty-four thousand, seven hundred forty-two".