840640220 has 96 divisors (see below), whose sum is σ = 2083777920. Its totient is φ = 278876160.

The previous prime is 840640219. The next prime is 840640249. The reversal of 840640220 is 22046048.

840640220 = T₇₁ + T₇₂ + ... + T₁₇₁₄.

840640220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 840640220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 785846 + ... + 786914.

It is an arithmetic number, because the mean of its divisors is an integer number (21706020).

Almost surely, 2^840640220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 840640220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1041888960).

840640220 is an abundant number, since it is smaller than the sum of its proper divisors (1243137700).

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

840640220 is a wasteful number, since it uses less digits than its factorization.

840640220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1263 (or 1261 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 840640220 is about 28993.7962329875. The cubic root of 840640220 is about 943.7784464621.

Adding to 840640220 its reverse (22046048), we get a palindrome (862686268).

The spelling of 840640220 in words is "eight hundred forty million, six hundred forty thousand, two hundred twenty".