991827000091 has 8 divisors (see below), whose sum is σ = 993206096064. Its totient is φ = 990448542720.

The previous prime is 991827000089. The next prime is 991827000097. The reversal of 991827000091 is 190000728199.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 991827000091 - 2¹ = 991827000089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991827000097) 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, 2991861 + ... + 3306793.

It is an arithmetic number, because the mean of its divisors is an integer number (124150762008).

Almost surely, 2^991827000091 is an apocalyptic number.

991827000091 is the 629866-th heptagonal number.

991827000091 is a deficient number, since it is larger than the sum of its proper divisors (1379095973).

991827000091 is a wasteful number, since it uses less digits than its factorization.

991827000091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319301.

The product of its (nonzero) digits is 81648, while the sum is 46.

The spelling of 991827000091 in words is "nine hundred ninety-one billion, eight hundred twenty-seven million, ninety-one", and thus it is an aban number.