991121022001111 has 4 divisors (see below), whose sum is σ = 991123612947000. Its totient is φ = 991118431055224.

The previous prime is 991121022001087. The next prime is 991121022001247. The reversal of 991121022001111 is 111100220121199.

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 991121022001111 - 2¹³ = 991121021992919 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 (991121022601111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1294899061 + ... + 1295664238.

It is an arithmetic number, because the mean of its divisors is an integer number (247780903236750).

Almost surely, 2^{991121022001111} is an apocalyptic number.

991121022001111 is a deficient number, since it is larger than the sum of its proper divisors (2590945889).

991121022001111 is a wasteful number, since it uses less digits than its factorization.

991121022001111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2590945888.

The product of its (nonzero) digits is 648, while the sum is 31.

The spelling of 991121022001111 in words is "nine hundred ninety-one trillion, one hundred twenty-one billion, twenty-two million, one thousand, one hundred eleven".