643639744746 has 24 divisors (see below), whose sum is σ = 1394888252160. Its totient is φ = 214494970536.

The previous prime is 643639744733. The next prime is 643639744757. The reversal of 643639744746 is 647447936346.

643639744746 is a `hidden beast` number, since 6 + 4 + 3 + 63 + 97 + 447 + 46 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4223980 + ... + 4373703.

It is an arithmetic number, because the mean of its divisors is an integer number (58120343840).

Almost surely, 2^643639744746 is an apocalyptic number.

643639744746 is an abundant number, since it is smaller than the sum of its proper divisors (751248507414).

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

643639744746 is a wasteful number, since it uses less digits than its factorization.

643639744746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8601850 (or 8601847 counting only the distinct ones).

The product of its digits is 219469824, while the sum is 63.

The spelling of 643639744746 in words is "six hundred forty-three billion, six hundred thirty-nine million, seven hundred forty-four thousand, seven hundred forty-six".