643634824218 has 16 divisors (see below), whose sum is σ = 1317206152416. Its totient is φ = 209555524080.

The previous prime is 643634824201. The next prime is 643634824229. The reversal of 643634824218 is 812428436346.

It is a super-2 number, since 2×643634824218² (a number of 24 digits) contains 22 as substring.

It is a Curzon 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, 1247354053 + ... + 1247354568.

It is an arithmetic number, because the mean of its divisors is an integer number (82325384526).

Almost surely, 2^643634824218 is an apocalyptic number.

643634824218 is an abundant number, since it is smaller than the sum of its proper divisors (673571328198).

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

643634824218 is a wasteful number, since it uses less digits than its factorization.

643634824218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2494708669.

The product of its digits is 5308416, while the sum is 51.

The spelling of 643634824218 in words is "six hundred forty-three billion, six hundred thirty-four million, eight hundred twenty-four thousand, two hundred eighteen".