991100001 has 16 divisors (see below), whose sum is σ = 1345721408. Its totient is φ = 648648000.

The previous prime is 991099973. The next prime is 991100081. The reversal of 991100001 is 100001199.

It is not a de Polignac number, because 991100001 - 2⁶ = 991099937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991100081) 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, 95151 + ... + 105051.

It is an arithmetic number, because the mean of its divisors is an integer number (84107588).

Almost surely, 2^991100001 is an apocalyptic number.

It is an amenable number.

991100001 is a deficient number, since it is larger than the sum of its proper divisors (354621407).

991100001 is a wasteful number, since it uses less digits than its factorization.

991100001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10512.

The product of its (nonzero) digits is 81, while the sum is 21.

The square root of 991100001 is about 31481.7407555554. The cubic root of 991100001 is about 997.0244887810.

The spelling of 991100001 in words is "nine hundred ninety-one million, one hundred thousand, one".