643156531265 has 16 divisors (see below), whose sum is σ = 790982433360. Its totient is φ = 501740590080.

The previous prime is 643156531253. The next prime is 643156531279. The reversal of 643156531265 is 562135651346.

It can be written as a sum of positive squares in 8 ways, for example, as 458908695184 + 184247836081 = 677428^2 + 429241^2 .

It is not a de Polignac number, because 643156531265 - 2²⁰ = 643155482689 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 295970 + ... + 1172139.

It is an arithmetic number, because the mean of its divisors is an integer number (49436402085).

Almost surely, 2^643156531265 is an apocalyptic number.

It is an amenable number.

643156531265 is a deficient number, since it is larger than the sum of its proper divisors (147825902095).

643156531265 is a wasteful number, since it uses less digits than its factorization.

643156531265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1470292.

The product of its digits is 1944000, while the sum is 47.

The spelling of 643156531265 in words is "six hundred forty-three billion, one hundred fifty-six million, five hundred thirty-one thousand, two hundred sixty-five".