1099991001 has 16 divisors (see below), whose sum is σ = 1574805888. Its totient is φ = 680467200.

The previous prime is 1099990987. The next prime is 1099991003. The reversal of 1099991001 is 1001999901.

It is not a de Polignac number, because 1099991001 - 2¹⁸ = 1099728857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1099991003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 148270 + ... + 155511.

It is an arithmetic number, because the mean of its divisors is an integer number (98425368).

Almost surely, 2^1099991001 is an apocalyptic number.

It is an amenable number.

1099991001 is a deficient number, since it is larger than the sum of its proper divisors (474814887).

1099991001 is a wasteful number, since it uses less digits than its factorization.

1099991001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303872.

The product of its (nonzero) digits is 6561, while the sum is 39.

The square root of 1099991001 is about 33166.1122382470. The cubic root of 1099991001 is about 1032.2773004521.

It can be divided in two parts, 10 and 99991001, that added together give a triangular number (99991011 = T₁₄₁₄₁).

The spelling of 1099991001 in words is "one billion, ninety-nine million, nine hundred ninety-one thousand, one".