991730 has 8 divisors (see below), whose sum is σ = 1785132. Its totient is φ = 396688.

The previous prime is 991723. The next prime is 991733. The reversal of 991730 is 37199.

It can be written as a sum of positive squares in 2 ways, for example, as 908209 + 83521 = 953^2 + 289^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 991693 and 991702.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991730.

It is not an unprimeable number, because it can be changed into a prime (991733) by changing a digit.

991730 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49577 + ... + 49596.

2⁹⁹¹⁷³⁰ is an apocalyptic number.

991730 is a deficient number, since it is larger than the sum of its proper divisors (793402).

991730 is a wasteful number, since it uses less digits than its factorization.

991730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99180.

The product of its (nonzero) digits is 1701, while the sum is 29.

The square root of 991730 is about 995.8564153531. The cubic root of 991730 is about 99.7235699014.

The spelling of 991730 in words is "nine hundred ninety-one thousand, seven hundred thirty".