991749 has 16 divisors (see below), whose sum is σ = 1479744. Its totient is φ = 585600.

The previous prime is 991741. The next prime is 991751. The reversal of 991749 is 947199.

It is not a de Polignac number, because 991749 - 2³ = 991741 is a prime.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 987 + ... + 1719.

It is an arithmetic number, because the mean of its divisors is an integer number (92484).

2⁹⁹¹⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

991749 is a deficient number, since it is larger than the sum of its proper divisors (487995).

991749 is a wasteful number, since it uses less digits than its factorization.

991749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788.

The product of its digits is 20412, while the sum is 39.

The square root of 991749 is about 995.8659548353. The cubic root of 991749 is about 99.7242067467.

The spelling of 991749 in words is "nine hundred ninety-one thousand, seven hundred forty-nine".