991202221121201 has 4 divisors (see below), whose sum is σ = 996931713729012. Its totient is φ = 985472728513392.

The previous prime is 991202221121153. The next prime is 991202221121219. The reversal of 991202221121201 is 102121122202199.

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

It can be written as a sum of positive squares in 2 ways, for example, as 926134621651600 + 65067599469601 = 30432460^2 + 8066449^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991202221121201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991202221121221) 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, 2864746303646 + ... + 2864746303991.

It is an arithmetic number, because the mean of its divisors is an integer number (249232928432253).

Almost surely, 2^{991202221121201} is an apocalyptic number.

It is an amenable number.

991202221121201 is a deficient number, since it is larger than the sum of its proper divisors (5729492607811).

991202221121201 is a wasteful number, since it uses less digits than its factorization.

991202221121201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5729492607810.

The product of its (nonzero) digits is 5184, while the sum is 35.

The spelling of 991202221121201 in words is "nine hundred ninety-one trillion, two hundred two billion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred one".