991849837 has 16 divisors (see below), whose sum is σ = 1140318720. Its totient is φ = 853210800.

The previous prime is 991849823. The next prime is 991849847. The reversal of 991849837 is 738948199.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 991849837 - 2¹⁹ = 991325549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991849847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 213178 + ... + 217780.

It is an arithmetic number, because the mean of its divisors is an integer number (71269920).

Almost surely, 2^991849837 is an apocalyptic number.

It is an amenable number.

991849837 is a deficient number, since it is larger than the sum of its proper divisors (148468883).

991849837 is a wasteful number, since it uses less digits than its factorization.

991849837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5664.

The product of its digits is 3919104, while the sum is 58.

The square root of 991849837 is about 31493.6475658187. The cubic root of 991849837 is about 997.2758648261.

The spelling of 991849837 in words is "nine hundred ninety-one million, eight hundred forty-nine thousand, eight hundred thirty-seven".