991109901 has 8 divisors (see below), whose sum is σ = 1391031520. Its totient is φ = 625964112.

The previous prime is 991109891. The next prime is 991109909. The reversal of 991109901 is 109901199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991109901 - 2⁶ = 991109837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991109901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991109909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8693890 + ... + 8694003.

It is an arithmetic number, because the mean of its divisors is an integer number (173878940).

Almost surely, 2^991109901 is an apocalyptic number.

It is an amenable number.

991109901 is a deficient number, since it is larger than the sum of its proper divisors (399921619).

991109901 is a wasteful number, since it uses less digits than its factorization.

991109901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17387915.

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

The square root of 991109901 is about 31481.8979891620. The cubic root of 991109901 is about 997.0278084964.

The spelling of 991109901 in words is "nine hundred ninety-one million, one hundred nine thousand, nine hundred one".