399228997991 has 2 divisors, whose sum is σ = 399228997992. Its totient is φ = 399228997990.

The previous prime is 399228997969. The next prime is 399228997997. The reversal of 399228997991 is 199799822993.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399228997991 - 2⁶ = 399228997927 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399228997997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199614498995 + 199614498996.

It is an arithmetic number, because the mean of its divisors is an integer number (199614498996).

Almost surely, 2^399228997991 is an apocalyptic number.

399228997991 is a deficient number, since it is larger than the sum of its proper divisors (1).

399228997991 is an equidigital number, since it uses as much as digits as its factorization.

399228997991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 357128352, while the sum is 77.

The spelling of 399228997991 in words is "three hundred ninety-nine billion, two hundred twenty-eight million, nine hundred ninety-seven thousand, nine hundred ninety-one".