643740650173 has 8 divisors (see below), whose sum is σ = 682381438200. Its totient is φ = 605185827840.

The previous prime is 643740650171. The next prime is 643740650177. The reversal of 643740650173 is 371056047346.

It can be written as a sum of positive squares in 4 ways, for example, as 291727453924 + 352013196249 = 540118^2 + 593307^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643740650173 - 2¹ = 643740650171 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643740650171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21475998 + ... + 21505951.

It is an arithmetic number, because the mean of its divisors is an integer number (85297679775).

Almost surely, 2^643740650173 is an apocalyptic number.

It is an amenable number.

643740650173 is a deficient number, since it is larger than the sum of its proper divisors (38640788027).

643740650173 is a wasteful number, since it uses less digits than its factorization.

643740650173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42982847.

The product of its (nonzero) digits is 1270080, while the sum is 46.

The spelling of 643740650173 in words is "six hundred forty-three billion, seven hundred forty million, six hundred fifty thousand, one hundred seventy-three".