991617 has 16 divisors (see below), whose sum is σ = 1459200. Its totient is φ = 594000.

The previous prime is 991607. The next prime is 991619. The reversal of 991617 is 716199.

It is not a de Polignac number, because 991617 - 2¹⁰ = 990593 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (991619) 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, 4884 + ... + 5082.

It is an arithmetic number, because the mean of its divisors is an integer number (91200).

2⁹⁹¹⁶¹⁷ is an apocalyptic number.

It is an amenable number.

991617 is a deficient number, since it is larger than the sum of its proper divisors (467583).

991617 is a wasteful number, since it uses less digits than its factorization.

991617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364.

The product of its digits is 3402, while the sum is 33.

The square root of 991617 is about 995.7996786503. The cubic root of 991617 is about 99.7197821798.

The spelling of 991617 in words is "nine hundred ninety-one thousand, six hundred seventeen".