9991919 has 8 divisors (see below), whose sum is σ = 11443200. Its totient is φ = 8546616.

The previous prime is 9991879. The next prime is 9991939. The reversal of 9991919 is 9191999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 9991919 - 2¹⁶ = 9926383 is a prime.

It is a super-2 number, since 2×9991919² = 199676890605122, 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 (9991939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3002 + ... + 5384.

It is an arithmetic number, because the mean of its divisors is an integer number (1430400).

Almost surely, 2^9991919 is an apocalyptic number.

9991919 is a deficient number, since it is larger than the sum of its proper divisors (1451281).

9991919 is a wasteful number, since it uses less digits than its factorization.

9991919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2989.

The product of its digits is 59049, while the sum is 47.

The square root of 9991919 is about 3160.9996836444. Note that the first 3 decimals coincide. The cubic root of 9991919 is about 215.3854200748.

The spelling of 9991919 in words is "nine million, nine hundred ninety-one thousand, nine hundred nineteen".