9991009001 has 16 divisors (see below), whose sum is σ = 10738939200. Its totient is φ = 9267187968.

The previous prime is 9991008983. The next prime is 9991009033. The reversal of 9991009001 is 1009001999.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 9991009001 - 2²² = 9986814697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (9991009801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 163730 + ... + 216308.

It is an arithmetic number, because the mean of its divisors is an integer number (671183700).

Almost surely, 2^9991009001 is an apocalyptic number.

It is an amenable number.

9991009001 is a deficient number, since it is larger than the sum of its proper divisors (747930199).

9991009001 is a wasteful number, since it uses less digits than its factorization.

9991009001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52808.

The product of its (nonzero) digits is 6561, while the sum is 38.

The square root of 9991009001 is about 99955.0348956970. The cubic root of 9991009001 is about 2153.7888124189.

The spelling of 9991009001 in words is "nine billion, nine hundred ninety-one million, nine thousand, one".