643800139 has 2 divisors, whose sum is σ = 643800140. Its totient is φ = 643800138.

The previous prime is 643800089. The next prime is 643800173. The reversal of 643800139 is 931008346.

It is an a-pointer prime, because the next prime (643800173) can be obtained adding 643800139 to its sum of digits (34).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643800139 - 2⁹ = 643799627 is a prime.

It is not a weakly prime, because it can be changed into another prime (643800439) 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 as a sum of consecutive naturals, namely, 321900069 + 321900070.

It is an arithmetic number, because the mean of its divisors is an integer number (321900070).

Almost surely, 2^643800139 is an apocalyptic number.

643800139 is a deficient number, since it is larger than the sum of its proper divisors (1).

643800139 is an equidigital number, since it uses as much as digits as its factorization.

643800139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 643800139 is about 25373.2169619857. The cubic root of 643800139 is about 863.4761677215.

The spelling of 643800139 in words is "six hundred forty-three million, eight hundred thousand, one hundred thirty-nine".