991709927 has 16 divisors (see below), whose sum is σ = 1123635072. Its totient is φ = 868942080.

The previous prime is 991709911. The next prime is 991709951. The reversal of 991709927 is 729907199.

It is a cyclic number.

It is not a de Polignac number, because 991709927 - 2⁴ = 991709911 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 (991709227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5423 + ... + 44864.

It is an arithmetic number, because the mean of its divisors is an integer number (70227192).

Almost surely, 2^991709927 is an apocalyptic number.

991709927 is a deficient number, since it is larger than the sum of its proper divisors (131925145).

991709927 is a wasteful number, since it uses less digits than its factorization.

991709927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50378.

The product of its (nonzero) digits is 642978, while the sum is 53.

The square root of 991709927 is about 31491.4262458848. The cubic root of 991709927 is about 997.2289708232.

The spelling of 991709927 in words is "nine hundred ninety-one million, seven hundred nine thousand, nine hundred twenty-seven".