991303121311 has 4 divisors (see below), whose sum is σ = 992096800000. Its totient is φ = 990509442624.

The previous prime is 991303121309. The next prime is 991303121327. The reversal of 991303121311 is 113121303199.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 991303121311 - 2¹ = 991303121309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991303122311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 396837471 + ... + 396839968.

It is an arithmetic number, because the mean of its divisors is an integer number (248024200000).

Almost surely, 2^991303121311 is an apocalyptic number.

991303121311 is a deficient number, since it is larger than the sum of its proper divisors (793678689).

991303121311 is a wasteful number, since it uses less digits than its factorization.

991303121311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 793678688.

The product of its (nonzero) digits is 4374, while the sum is 34.

The spelling of 991303121311 in words is "nine hundred ninety-one billion, three hundred three million, one hundred twenty-one thousand, three hundred eleven".