645686143 has 2 divisors, whose sum is σ = 645686144. Its totient is φ = 645686142.

The previous prime is 645686089. The next prime is 645686179. The reversal of 645686143 is 341686546.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645686143 - 2²¹ = 643588991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645686143.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645687143) 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 as a sum of consecutive naturals, namely, 322843071 + 322843072.

It is an arithmetic number, because the mean of its divisors is an integer number (322843072).

Almost surely, 2^645686143 is an apocalyptic number.

645686143 is a deficient number, since it is larger than the sum of its proper divisors (1).

645686143 is an equidigital number, since it uses as much as digits as its factorization.

645686143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 414720, while the sum is 43.

The square root of 645686143 is about 25410.3550349065. The cubic root of 645686143 is about 864.3185263711.

The spelling of 645686143 in words is "six hundred forty-five million, six hundred eighty-six thousand, one hundred forty-three".