991111111201 has 16 divisors (see below), whose sum is σ = 1012225204224. Its totient is φ = 970203619584.

The previous prime is 991111111171. The next prime is 991111111213. The reversal of 991111111201 is 102111111199.

It is a cyclic number.

It is not a de Polignac number, because 991111111201 - 2¹⁹ = 991110586913 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 991111111201.

It is not an unprimeable number, because it can be changed into a prime (991111111271) 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, 93434040 + ... + 93444646.

It is an arithmetic number, because the mean of its divisors is an integer number (63264075264).

Almost surely, 2^991111111201 is an apocalyptic number.

It is an amenable number.

991111111201 is a deficient number, since it is larger than the sum of its proper divisors (21114093023).

991111111201 is a wasteful number, since it uses less digits than its factorization.

991111111201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20160.

The product of its (nonzero) digits is 162, while the sum is 28.

The spelling of 991111111201 in words is "nine hundred ninety-one billion, one hundred eleven million, one hundred eleven thousand, two hundred one".