999971899 has 2 divisors, whose sum is σ = 999971900. Its totient is φ = 999971898.

The previous prime is 999971849. The next prime is 999971969. The reversal of 999971899 is 998179999.

It is an a-pointer prime, because the next prime (999971969) can be obtained adding 999971899 to its sum of digits (70).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999971899 - 2⁷ = 999971771 is a prime.

It is not a weakly prime, because it can be changed into another prime (999971849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499985949 + 499985950.

It is an arithmetic number, because the mean of its divisors is an integer number (499985950).

Almost surely, 2^999971899 is an apocalyptic number.

999971899 is a deficient number, since it is larger than the sum of its proper divisors (1).

999971899 is an equidigital number, since it uses as much as digits as its factorization.

999971899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29760696, while the sum is 70.

The square root of 999971899 is about 31622.3322827397. The cubic root of 999971899 is about 999.9906329123.

The spelling of 999971899 in words is "nine hundred ninety-nine million, nine hundred seventy-one thousand, eight hundred ninety-nine".