643265215533 has 12 divisors (see below), whose sum is σ = 929173628188. Its totient is φ = 428837587200.

The previous prime is 643265215507. The next prime is 643265215561. The reversal of 643265215533 is 335512562346.

643265215533 is a `hidden beast` number, since 6 + 4 + 32 + 65 + 2 + 1 + 553 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 213982106724 + 429283108809 = 462582^2 + 655197^2 .

It is not a de Polignac number, because 643265215533 - 2⁵ = 643265215501 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 (643263215533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 261591 + ... + 1164027.

Almost surely, 2^643265215533 is an apocalyptic number.

It is an amenable number.

643265215533 is a deficient number, since it is larger than the sum of its proper divisors (285908412655).

643265215533 is a wasteful number, since it uses less digits than its factorization.

643265215533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981644 (or 981641 counting only the distinct ones).

The product of its digits is 1944000, while the sum is 45.

Adding to 643265215533 its reverse (335512562346), we get a palindrome (978777777879).

The spelling of 643265215533 in words is "six hundred forty-three billion, two hundred sixty-five million, two hundred fifteen thousand, five hundred thirty-three".