999999919 has 4 divisors (see below), whose sum is σ = 1018867896. Its totient is φ = 981131944.

The previous prime is 999999893. The next prime is 999999929. The reversal of 999999919 is 919999999.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 999999919 - 2¹¹ = 999997871 is a prime.

It is a super-2 number, since 2×999999919² = 1999999676000013122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999999929) 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 in 3 ways as a sum of consecutive naturals, for example, 9433909 + ... + 9434014.

It is an arithmetic number, because the mean of its divisors is an integer number (254716974).

Almost surely, 2^999999919 is an apocalyptic number.

999999919 is a deficient number, since it is larger than the sum of its proper divisors (18867977).

999999919 is a wasteful number, since it uses less digits than its factorization.

999999919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18867976.

The product of its digits is 43046721, while the sum is 73.

The square root of 999999919 is about 31622.7753209613. The cubic root of 999999919 is about 999.9999730000. Note that the first 4 decimals are identical.

It can be divided in two parts, 99999991 and 9, that added together give a 8-th power (100000000 = 10⁸).

The spelling of 999999919 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred nineteen".