643956115293 has 6 divisors (see below), whose sum is σ = 930158833214. Its totient is φ = 429304076856.

The previous prime is 643956115267. The next prime is 643956115307. The reversal of 643956115293 is 392511659346.

643956115293 is a `hidden beast` number, since 6 + 43 + 9 + 561 + 15 + 29 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 617989371129 + 25966744164 = 786123^2 + 161142^2 .

It is not a de Polignac number, because 643956115293 - 2¹³ = 643956107101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643956115393) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 35775339730 + ... + 35775339747.

Almost surely, 2^643956115293 is an apocalyptic number.

It is an amenable number.

643956115293 is a deficient number, since it is larger than the sum of its proper divisors (286202717921).

643956115293 is a wasteful number, since it uses less digits than its factorization.

643956115293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71550679483 (or 71550679480 counting only the distinct ones).

The product of its digits is 5248800, while the sum is 54.

The spelling of 643956115293 in words is "six hundred forty-three billion, nine hundred fifty-six million, one hundred fifteen thousand, two hundred ninety-three".