991120201001201 has 2 divisors, whose sum is σ = 991120201001202. Its totient is φ = 991120201001200.

The previous prime is 991120201001197. The next prime is 991120201001209. The reversal of 991120201001201 is 102100102021199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 979614944037601 + 11505256963600 = 31298801^2 + 3391940^2 .

It is an emirp because it is prime and its reverse (102100102021199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 991120201001201 - 2² = 991120201001197 is a prime.

It is a super-2 number, since 2×991120201001201² (a number of 31 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (991120201001209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495560100500600 + 495560100500601.

It is an arithmetic number, because the mean of its divisors is an integer number (495560100500601).

Almost surely, 2^{991120201001201} is an apocalyptic number.

It is an amenable number.

991120201001201 is a deficient number, since it is larger than the sum of its proper divisors (1).

991120201001201 is an equidigital number, since it uses as much as digits as its factorization.

991120201001201 is an evil number, because the sum of its binary digits is even.

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

The spelling of 991120201001201 in words is "nine hundred ninety-one trillion, one hundred twenty billion, two hundred one million, one thousand, two hundred one".