991193543 has 4 divisors (see below), whose sum is σ = 993493728. Its totient is φ = 988893360.

The previous prime is 991193527. The next prime is 991193549. The reversal of 991193543 is 345391199.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 991193543 - 2⁴ = 991193527 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991193494 and 991193503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991193549) 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, 1149446 + ... + 1150307.

It is an arithmetic number, because the mean of its divisors is an integer number (248373432).

Almost surely, 2^991193543 is an apocalyptic number.

991193543 is a deficient number, since it is larger than the sum of its proper divisors (2300185).

991193543 is a wasteful number, since it uses less digits than its factorization.

991193543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2300184.

The product of its digits is 131220, while the sum is 44.

The square root of 991193543 is about 31483.2263753256. The cubic root of 991193543 is about 997.0558548493.

The spelling of 991193543 in words is "nine hundred ninety-one million, one hundred ninety-three thousand, five hundred forty-three".