991297920047 has 2 divisors, whose sum is σ = 991297920048. Its totient is φ = 991297920046.

The previous prime is 991297919959. The next prime is 991297920061. The reversal of 991297920047 is 740029792199.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 991297920047 - 2⁸ = 991297919791 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991297920077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495648960023 + 495648960024.

It is an arithmetic number, because the mean of its divisors is an integer number (495648960024).

Almost surely, 2^991297920047 is an apocalyptic number.

991297920047 is a deficient number, since it is larger than the sum of its proper divisors (1).

991297920047 is an equidigital number, since it uses as much as digits as its factorization.

991297920047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5143824, while the sum is 59.

The spelling of 991297920047 in words is "nine hundred ninety-one billion, two hundred ninety-seven million, nine hundred twenty thousand, forty-seven".