991519 has 4 divisors (see below), whose sum is σ = 993744. Its totient is φ = 989296.

The previous prime is 991511. The next prime is 991531. The reversal of 991519 is 915199.

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 991519 - 2³ = 991511 is a prime.

It is a super-2 number, since 2×991519² = 1966219854722, 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 (991511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 187 + ... + 1420.

It is an arithmetic number, because the mean of its divisors is an integer number (248436).

2⁹⁹¹⁵¹⁹ is an apocalyptic number.

991519 is a deficient number, since it is larger than the sum of its proper divisors (2225).

991519 is a wasteful number, since it uses less digits than its factorization.

991519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224.

The product of its digits is 3645, while the sum is 34.

The square root of 991519 is about 995.7504707506. The cubic root of 991519 is about 99.7164970201.

The spelling of 991519 in words is "nine hundred ninety-one thousand, five hundred nineteen".