991844729 has 4 divisors (see below), whose sum is σ = 995013876. Its totient is φ = 988675584.

The previous prime is 991844717. The next prime is 991844743. The reversal of 991844729 is 927448199.

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

It can be written as a sum of positive squares in 2 ways, for example, as 178169104 + 813675625 = 13348^2 + 28525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991844729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991844129) 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, 1584104 + ... + 1584729.

It is an arithmetic number, because the mean of its divisors is an integer number (248753469).

Almost surely, 2^991844729 is an apocalyptic number.

It is an amenable number.

991844729 is a deficient number, since it is larger than the sum of its proper divisors (3169147).

991844729 is a wasteful number, since it uses less digits than its factorization.

991844729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3169146.

The product of its digits is 1306368, while the sum is 53.

The square root of 991844729 is about 31493.5664699951. The cubic root of 991844729 is about 997.2741528418.

The spelling of 991844729 in words is "nine hundred ninety-one million, eight hundred forty-four thousand, seven hundred twenty-nine".