645623544013 has 16 divisors (see below), whose sum is σ = 777097566720. Its totient is φ = 523990612656.

The previous prime is 645623543951. The next prime is 645623544023. The reversal of 645623544013 is 310445326546.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-645623544013 is a prime.

It is a super-2 number, since 2×645623544013² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645623544023) 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 15 ways as a sum of consecutive naturals, for example, 1019131 + ... + 1526392.

It is an arithmetic number, because the mean of its divisors is an integer number (48568597920).

Almost surely, 2^645623544013 is an apocalyptic number.

It is an amenable number.

645623544013 is a deficient number, since it is larger than the sum of its proper divisors (131474022707).

645623544013 is a wasteful number, since it uses less digits than its factorization.

645623544013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2547456.

The product of its (nonzero) digits is 1036800, while the sum is 43.

The spelling of 645623544013 in words is "six hundred forty-five billion, six hundred twenty-three million, five hundred forty-four thousand, thirteen".