640833798 has 64 divisors (see below), whose sum is σ = 1458616320. Its totient is φ = 185932800.

The previous prime is 640833763. The next prime is 640833799. The reversal of 640833798 is 897338046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640833799) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 196848 + ... + 200076.

It is an arithmetic number, because the mean of its divisors is an integer number (22790880).

Almost surely, 2^640833798 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640833798, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (729308160).

640833798 is an abundant number, since it is smaller than the sum of its proper divisors (817782522).

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

640833798 is a wasteful number, since it uses less digits than its factorization.

640833798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3373.

The product of its (nonzero) digits is 870912, while the sum is 48.

The square root of 640833798 is about 25314.6952973959. The cubic root of 640833798 is about 862.1479559697.

It can be divided in two parts, 640 and 833798, that added together give a palindrome (834438).

The spelling of 640833798 in words is "six hundred forty million, eight hundred thirty-three thousand, seven hundred ninety-eight".