991943841 has 32 divisors (see below), whose sum is σ = 1555142400. Its totient is φ = 550526976.

The previous prime is 991943831. The next prime is 991943867. The reversal of 991943841 is 148349199.

It is not a de Polignac number, because 991943841 - 2⁷ = 991943713 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (991943801) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 814465 + ... + 815681.

It is an arithmetic number, because the mean of its divisors is an integer number (48598200).

Almost surely, 2^991943841 is an apocalyptic number.

It is an amenable number.

991943841 is a deficient number, since it is larger than the sum of its proper divisors (563198559).

991943841 is a wasteful number, since it uses less digits than its factorization.

991943841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2313.

The product of its digits is 279936, while the sum is 48.

The square root of 991943841 is about 31495.1399584126. The cubic root of 991943841 is about 997.3073699173.

The spelling of 991943841 in words is "nine hundred ninety-one million, nine hundred forty-three thousand, eight hundred forty-one".