99991145 has 4 divisors (see below), whose sum is σ = 119989380. Its totient is φ = 79992912.

The previous prime is 99991109. The next prime is 99991207. The reversal of 99991145 is 54119999.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54119999 = 19 ⋅2848421.

It can be written as a sum of positive squares in 2 ways, for example, as 11235904 + 88755241 = 3352^2 + 9421^2 .

It is a cyclic number.

It is not a de Polignac number, because 99991145 - 2⁶ = 99991081 is a prime.

It is a super-2 number, since 2×99991145² = 19996458156822050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 99991145.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9999110 + ... + 9999119.

It is an arithmetic number, because the mean of its divisors is an integer number (29997345).

Almost surely, 2^99991145 is an apocalyptic number.

It is an amenable number.

99991145 is a deficient number, since it is larger than the sum of its proper divisors (19998235).

99991145 is a wasteful number, since it uses less digits than its factorization.

99991145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19998234.

The product of its digits is 131220, while the sum is 47.

The square root of 99991145 is about 9999.5572401982. The cubic root of 99991145 is about 464.1451825338.

The spelling of 99991145 in words is "ninety-nine million, nine hundred ninety-one thousand, one hundred forty-five".