645612165533 has 4 divisors (see below), whose sum is σ = 645614987040. Its totient is φ = 645609344028.

The previous prime is 645612165511. The next prime is 645612165589. The reversal of 645612165533 is 335561216546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645612165533 - 2²⁸ = 645343730077 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 (645612168533) 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 3 ways as a sum of consecutive naturals, for example, 1033985 + ... + 1536342.

It is an arithmetic number, because the mean of its divisors is an integer number (161403746760).

Almost surely, 2^645612165533 is an apocalyptic number.

It is an amenable number.

645612165533 is a deficient number, since it is larger than the sum of its proper divisors (2821507).

645612165533 is a wasteful number, since it uses less digits than its factorization.

645612165533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2821506.

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

The spelling of 645612165533 in words is "six hundred forty-five billion, six hundred twelve million, one hundred sixty-five thousand, five hundred thirty-three".