1115555999 has 4 divisors (see below), whose sum is σ = 1125981864. Its totient is φ = 1105130136.

The previous prime is 1115555989. The next prime is 1115556059. The reversal of 1115555999 is 9995555111.

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 1115555999 - 2¹⁶ = 1115490463 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1115555989) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5212772 + ... + 5212985.

It is an arithmetic number, because the mean of its divisors is an integer number (281495466).

Almost surely, 2^1115555999 is an apocalyptic number.

1115555999 is a deficient number, since it is larger than the sum of its proper divisors (10425865).

1115555999 is a wasteful number, since it uses less digits than its factorization.

1115555999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10425864.

The product of its digits is 455625, while the sum is 50.

The square root of 1115555999 is about 33399.9401047367. The cubic root of 1115555999 is about 1037.1234610564.

The spelling of 1115555999 in words is "one billion, one hundred fifteen million, five hundred fifty-five thousand, nine hundred ninety-nine".