645839911331 has 4 divisors (see below), whose sum is σ = 645845972112. Its totient is φ = 645833850552.

The previous prime is 645839911279. The next prime is 645839911351. The reversal of 645839911331 is 133119938546.

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 645839911331 - 2¹⁸ = 645839649187 is a prime.

It is a super-2 number, since 2×645839911331² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645839911351) 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, 2867636 + ... + 3084641.

It is an arithmetic number, because the mean of its divisors is an integer number (161461493028).

Almost surely, 2^645839911331 is an apocalyptic number.

645839911331 is a deficient number, since it is larger than the sum of its proper divisors (6060781).

645839911331 is a wasteful number, since it uses less digits than its factorization.

645839911331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6060780.

The product of its digits is 2099520, while the sum is 53.

The spelling of 645839911331 in words is "six hundred forty-five billion, eight hundred thirty-nine million, nine hundred eleven thousand, three hundred thirty-one".