991211220011 has 8 divisors (see below), whose sum is σ = 992810167440. Its totient is φ = 989612521632.

The previous prime is 991211219923. The next prime is 991211220059. The reversal of 991211220011 is 110022112199.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991211220011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991211220071) 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, 8949176 + ... + 9059258.

It is an arithmetic number, because the mean of its divisors is an integer number (124101270930).

Almost surely, 2^991211220011 is an apocalyptic number.

991211220011 is a deficient number, since it is larger than the sum of its proper divisors (1598947429).

991211220011 is a wasteful number, since it uses less digits than its factorization.

991211220011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124525.

The product of its (nonzero) digits is 648, while the sum is 29.

The spelling of 991211220011 in words is "nine hundred ninety-one billion, two hundred eleven million, two hundred twenty thousand, eleven".