645169656763 has 4 divisors (see below), whose sum is σ = 652418754120. Its totient is φ = 637920559408.

The previous prime is 645169656739. The next prime is 645169656773. The reversal of 645169656763 is 367656961546.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645169656763 - 2⁹ = 645169656251 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645169656695 and 645169656704.

It is not an unprimeable number, because it can be changed into a prime (645169656773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3624548545 + ... + 3624548722.

It is an arithmetic number, because the mean of its divisors is an integer number (163104688530).

Almost surely, 2^645169656763 is an apocalyptic number.

645169656763 is a deficient number, since it is larger than the sum of its proper divisors (7249097357).

645169656763 is an equidigital number, since it uses as much as digits as its factorization.

645169656763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7249097356.

The product of its digits is 146966400, while the sum is 64.

It can be divided in two parts, 64516 and 9656763, that added together give a palindrome (9721279).

The spelling of 645169656763 in words is "six hundred forty-five billion, one hundred sixty-nine million, six hundred fifty-six thousand, seven hundred sixty-three".