991297920011 has 8 divisors (see below), whose sum is σ = 1133436179424. Its totient is φ = 849290728320.

The previous prime is 991297919959. The next prime is 991297920047. The reversal of 991297920011 is 110029792199.

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 991297920011 - 2⁶ = 991297919947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991297920061) 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, 32750720 + ... + 32780973.

It is an arithmetic number, because the mean of its divisors is an integer number (141679522428).

Almost surely, 2^991297920011 is an apocalyptic number.

991297920011 is a deficient number, since it is larger than the sum of its proper divisors (142138259413).

991297920011 is a wasteful number, since it uses less digits than its factorization.

991297920011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65533861.

The product of its (nonzero) digits is 183708, while the sum is 50.

The spelling of 991297920011 in words is "nine hundred ninety-one billion, two hundred ninety-seven million, nine hundred twenty thousand, eleven".