991543246849 has 4 divisors (see below), whose sum is σ = 991595367360. Its totient is φ = 991491126340.

The previous prime is 991543246829. The next prime is 991543246861. The reversal of 991543246849 is 948642345199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 948642345199 = 13331 ⋅71160629.

It is a cyclic number.

It is not a de Polignac number, because 991543246849 - 2⁷ = 991543246721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991543246829) 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, 26031709 + ... + 26069770.

It is an arithmetic number, because the mean of its divisors is an integer number (247898841840).

Almost surely, 2^991543246849 is an apocalyptic number.

It is an amenable number.

991543246849 is a deficient number, since it is larger than the sum of its proper divisors (52120511).

991543246849 is a wasteful number, since it uses less digits than its factorization.

991543246849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52120510.

The product of its digits is 67184640, while the sum is 64.

The spelling of 991543246849 in words is "nine hundred ninety-one billion, five hundred forty-three million, two hundred forty-six thousand, eight hundred forty-nine".