991545220111 has 8 divisors (see below), whose sum is σ = 1023969343104. Its totient is φ = 959148521760.

The previous prime is 991545220091. The next prime is 991545220129. The reversal of 991545220111 is 111022545199.

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 991545220111 - 2¹¹ = 991545218063 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 (991545290111) 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 7 ways as a sum of consecutive naturals, for example, 6782656 + ... + 6927301.

It is an arithmetic number, because the mean of its divisors is an integer number (127996167888).

Almost surely, 2^991545220111 is an apocalyptic number.

991545220111 is a deficient number, since it is larger than the sum of its proper divisors (32424122993).

991545220111 is a wasteful number, since it uses less digits than its factorization.

991545220111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13712321.

The product of its (nonzero) digits is 32400, while the sum is 40.

The spelling of 991545220111 in words is "nine hundred ninety-one billion, five hundred forty-five million, two hundred twenty thousand, one hundred eleven".