991740 has 24 divisors (see below), whose sum is σ = 2777040. Its totient is φ = 264448.

The previous prime is 991733. The next prime is 991741. The reversal of 991740 is 47199.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 991698 and 991707.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991740.

It is not an unprimeable number, because it can be changed into a prime (991741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8205 + ... + 8324.

It is an arithmetic number, because the mean of its divisors is an integer number (115710).

2⁹⁹¹⁷⁴⁰ is an apocalyptic number.

It is an amenable number.

991740 is an abundant number, since it is smaller than the sum of its proper divisors (1785300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991740 is a wasteful number, since it uses less digits than its factorization.

991740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16541 (or 16539 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 991740 is about 995.8614361446. The cubic root of 991740 is about 99.7239050842.

The spelling of 991740 in words is "nine hundred ninety-one thousand, seven hundred forty".