991002011 has 2 divisors, whose sum is σ = 991002012. Its totient is φ = 991002010.

The previous prime is 991001993. The next prime is 991002013. The reversal of 991002011 is 110200199.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 991002011 - 2¹⁰ = 991000987 is a prime.

Together with 991002013, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991002013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495501005 + 495501006.

It is an arithmetic number, because the mean of its divisors is an integer number (495501006).

Almost surely, 2^991002011 is an apocalyptic number.

991002011 is a deficient number, since it is larger than the sum of its proper divisors (1).

991002011 is an equidigital number, since it uses as much as digits as its factorization.

991002011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 991002011 is about 31480.1844181383. The cubic root of 991002011 is about 996.9916291135.

The spelling of 991002011 in words is "nine hundred ninety-one million, two thousand, eleven".