991937129 has 8 divisors (see below), whose sum is σ = 1010416680. Its totient is φ = 973620736.

The previous prime is 991937119. The next prime is 991937137. The reversal of 991937129 is 921739199.

It can be written as a sum of positive squares in 4 ways, for example, as 166926400 + 825010729 = 12920^2 + 28723^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991937129 - 2⁴ = 991937113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991937119) 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 7 ways as a sum of consecutive naturals, for example, 28484 + ... + 52869.

It is an arithmetic number, because the mean of its divisors is an integer number (126302085).

Almost surely, 2^991937129 is an apocalyptic number.

It is an amenable number.

991937129 is a deficient number, since it is larger than the sum of its proper divisors (18479551).

991937129 is a wasteful number, since it uses less digits than its factorization.

991937129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81579.

The product of its digits is 275562, while the sum is 50.

The square root of 991937129 is about 31495.0334021096. The cubic root of 991937129 is about 997.3051204815.

The spelling of 991937129 in words is "nine hundred ninety-one million, nine hundred thirty-seven thousand, one hundred twenty-nine".