1099999999 has 4 divisors (see below), whose sum is σ = 1257142864. Its totient is φ = 942857136.

The previous prime is 1099999997. The next prime is 1100000009. The reversal of 1099999999 is 9999999901.

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 1099999999 - 2¹ = 1099999997 is a prime.

It is a Duffinian number.

1099999999 is a modest number, since divided by 99999 gives 10999 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1099999997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78571422 + ... + 78571435.

It is an arithmetic number, because the mean of its divisors is an integer number (314285716).

Almost surely, 2^1099999999 is an apocalyptic number.

1099999999 is a deficient number, since it is larger than the sum of its proper divisors (157142865).

1099999999 is an equidigital number, since it uses as much as digits as its factorization.

1099999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157142864.

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

The square root of 1099999999 is about 33166.2478884784. The cubic root of 1099999999 is about 1032.2801151436.

It can be divided in two parts, 1099 and 999999, that multiplied together give a palindrome (1098998901).

The spelling of 1099999999 in words is "one billion, ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".