645643641426 has 16 divisors (see below), whose sum is σ = 1475756894784. Its totient is φ = 184469611824.

The previous prime is 645643641421. The next prime is 645643641431. The reversal of 645643641426 is 624146346546.

It is an interprime number because it is at equal distance from previous prime (645643641421) and next prime (645643641431).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645643641421) 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, 7686233785 + ... + 7686233868.

It is an arithmetic number, because the mean of its divisors is an integer number (92234805924).

Almost surely, 2^645643641426 is an apocalyptic number.

645643641426 is an abundant number, since it is smaller than the sum of its proper divisors (830113253358).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645643641426 is a wasteful number, since it uses less digits than its factorization.

645643641426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15372467665.

The product of its digits is 9953280, while the sum is 51.

The spelling of 645643641426 in words is "six hundred forty-five billion, six hundred forty-three million, six hundred forty-one thousand, four hundred twenty-six".