6399203891 has 2 divisors, whose sum is σ = 6399203892. Its totient is φ = 6399203890.

The previous prime is 6399203849. The next prime is 6399203917. The reversal of 6399203891 is 1983029936.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6399203891 - 2⁶ = 6399203827 is a prime.

It is not a weakly prime, because it can be changed into another prime (6399208891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3199601945 + 3199601946.

It is an arithmetic number, because the mean of its divisors is an integer number (3199601946).

Almost surely, 2^6399203891 is an apocalyptic number.

6399203891 is a deficient number, since it is larger than the sum of its proper divisors (1).

6399203891 is an equidigital number, since it uses as much as digits as its factorization.

6399203891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 629856, while the sum is 50.

The square root of 6399203891 is about 79995.0241640066. The cubic root of 6399203891 is about 1856.5585466977.

The spelling of 6399203891 in words is "six billion, three hundred ninety-nine million, two hundred three thousand, eight hundred ninety-one".