991384138033 has 2 divisors, whose sum is σ = 991384138034. Its totient is φ = 991384138032.

The previous prime is 991384138021. The next prime is 991384138079. The reversal of 991384138033 is 330831483199.

991384138033 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 931423800609 + 59960337424 = 965103^2 + 244868^2 .

It is a cyclic number.

It is not a de Polignac number, because 991384138033 - 2²⁹ = 990847267121 is a prime.

It is not a weakly prime, because it can be changed into another prime (991384136033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495692069016 + 495692069017.

It is an arithmetic number, because the mean of its divisors is an integer number (495692069017).

Almost surely, 2^991384138033 is an apocalyptic number.

It is an amenable number.

991384138033 is a deficient number, since it is larger than the sum of its proper divisors (1).

991384138033 is an equidigital number, since it uses as much as digits as its factorization.

991384138033 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1679616, while the sum is 52.

The spelling of 991384138033 in words is "nine hundred ninety-one billion, three hundred eighty-four million, one hundred thirty-eight thousand, thirty-three".