645500056361 has 4 divisors (see below), whose sum is σ = 645501706500. Its totient is φ = 645498406224.

The previous prime is 645500056351. The next prime is 645500056373. The reversal of 645500056361 is 163650005546.

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

It can be written as a sum of positive squares in 2 ways, for example, as 68706894400 + 576793161961 = 262120^2 + 759469^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645500056361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645500056321) 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 3 ways as a sum of consecutive naturals, for example, 130955 + ... + 1143743.

It is an arithmetic number, because the mean of its divisors is an integer number (161375426625).

Almost surely, 2^645500056361 is an apocalyptic number.

It is an amenable number.

645500056361 is a deficient number, since it is larger than the sum of its proper divisors (1650139).

645500056361 is a wasteful number, since it uses less digits than its factorization.

645500056361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650138.

The product of its (nonzero) digits is 324000, while the sum is 41.

The spelling of 645500056361 in words is "six hundred forty-five billion, five hundred million, fifty-six thousand, three hundred sixty-one".