999915971 has 2 divisors, whose sum is σ = 999915972. Its totient is φ = 999915970.

The previous prime is 999915947. The next prime is 999915991. The reversal of 999915971 is 179519999.

999915971 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 999915971 - 2¹⁴ = 999899587 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 999915971.

It is not a weakly prime, because it can be changed into another prime (999915901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499957985 + 499957986.

It is an arithmetic number, because the mean of its divisors is an integer number (499957986).

Almost surely, 2^999915971 is an apocalyptic number.

999915971 is a deficient number, since it is larger than the sum of its proper divisors (1).

999915971 is an equidigital number, since it uses as much as digits as its factorization.

999915971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2066715, while the sum is 59.

The square root of 999915971 is about 31621.4479586245. The cubic root of 999915971 is about 999.9719895488.

The spelling of 999915971 in words is "nine hundred ninety-nine million, nine hundred fifteen thousand, nine hundred seventy-one".