1001099999 has 4 divisors (see below), whose sum is σ = 1002897864. Its totient is φ = 999302136.

The previous prime is 1001099971. The next prime is 1001100007. The reversal of 1001099999 is 9999901001.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001099999 is a prime.

It is a Duffinian number.

1001099999 is a modest number, since divided by 99999 gives 10010 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001099599) 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, 898097 + ... + 899210.

It is an arithmetic number, because the mean of its divisors is an integer number (250724466).

Almost surely, 2^1001099999 is an apocalyptic number.

1001099999 is a deficient number, since it is larger than the sum of its proper divisors (1797865).

1001099999 is an equidigital number, since it uses as much as digits as its factorization.

1001099999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1797864.

The product of its (nonzero) digits is 59049, while the sum is 47.

The square root of 1001099999 is about 31640.1643326959. The cubic root of 1001099999 is about 1000.3665319712.

The spelling of 1001099999 in words is "one billion, one million, ninety-nine thousand, nine hundred ninety-nine".