645376673545 has 8 divisors (see below), whose sum is σ = 774500324040. Its totient is φ = 516269128320.

The previous prime is 645376673527. The next prime is 645376673549. The reversal of 645376673545 is 545376673546.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 56060979984 + 589315693561 = 236772^2 + 767669^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645376673545 - 2²³ = 645368284937 is a prime.

It is a super-2 number, since 2×645376673545² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645376673549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3937980 + ... + 4098589.

It is an arithmetic number, because the mean of its divisors is an integer number (96812540505).

Almost surely, 2^645376673545 is an apocalyptic number.

It is an amenable number.

645376673545 is a deficient number, since it is larger than the sum of its proper divisors (129123650495).

645376673545 is a wasteful number, since it uses less digits than its factorization.

645376673545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8052635.

The product of its digits is 190512000, while the sum is 61.

Subtracting from 645376673545 its reverse (545376673546), we obtain a palindrome (99999999999).

The spelling of 645376673545 in words is "six hundred forty-five billion, three hundred seventy-six million, six hundred seventy-three thousand, five hundred forty-five".