991543441 has 4 divisors (see below), whose sum is σ = 1133192512. Its totient is φ = 849894372.

The previous prime is 991543433. The next prime is 991543459. The reversal of 991543441 is 144345199.

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.

It is a cyclic number.

It is not a de Polignac number, because 991543441 - 2³ = 991543433 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991543394 and 991543403.

It is not an unprimeable number, because it can be changed into a prime (991543541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70824525 + ... + 70824538.

It is an arithmetic number, because the mean of its divisors is an integer number (283298128).

Almost surely, 2^991543441 is an apocalyptic number.

It is an amenable number.

991543441 is a deficient number, since it is larger than the sum of its proper divisors (141649071).

991543441 is a wasteful number, since it uses less digits than its factorization.

991543441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141649070.

The product of its digits is 77760, while the sum is 40.

The square root of 991543441 is about 31488.7827805395. The cubic root of 991543441 is about 997.1731635253.

The spelling of 991543441 in words is "nine hundred ninety-one million, five hundred forty-three thousand, four hundred forty-one".