3999991109971 has 2 divisors, whose sum is σ = 3999991109972. Its totient is φ = 3999991109970.

The previous prime is 3999991109953. The next prime is 3999991110007. The reversal of 3999991109971 is 1799011999993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 3999991109971 - 2⁷ = 3999991109843 is a prime.

It is not a weakly prime, because it can be changed into another prime (3999991109171) 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, 1999995554985 + 1999995554986.

It is an arithmetic number, because the mean of its divisors is an integer number (1999995554986).

Almost surely, 2^{3999991109971} is an apocalyptic number.

3999991109971 is a deficient number, since it is larger than the sum of its proper divisors (1).

3999991109971 is an equidigital number, since it uses as much as digits as its factorization.

3999991109971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100442349, while the sum is 76.

The spelling of 3999991109971 in words is "three trillion, nine hundred ninety-nine billion, nine hundred ninety-one million, one hundred nine thousand, nine hundred seventy-one".