640204822818 has 128 divisors (see below), whose sum is σ = 1607790919680. Its totient is φ = 187073712000.

The previous prime is 640204822799. The next prime is 640204822847. The reversal of 640204822818 is 818228402046.

640204822818 is a `hidden beast` number, since 6 + 402 + 0 + 4 + 8 + 228 + 18 = 666.

It is a super-3 number, since 3×640204822818³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5112471 + ... + 5236197.

It is an arithmetic number, because the mean of its divisors is an integer number (12560866560).

Almost surely, 2^640204822818 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640204822818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803895459840).

640204822818 is an abundant number, since it is smaller than the sum of its proper divisors (967586096862).

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

640204822818 is a wasteful number, since it uses less digits than its factorization.

640204822818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124061 (or 124055 counting only the distinct ones).

The product of its (nonzero) digits is 393216, while the sum is 45.

The spelling of 640204822818 in words is "six hundred forty billion, two hundred four million, eight hundred twenty-two thousand, eight hundred eighteen".