991560 has 32 divisors (see below), whose sum is σ = 2975040. Its totient is φ = 264384.

The previous prime is 991547. The next prime is 991567. The reversal of 991560 is 65199.

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

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991567) by changing a digit.

991560 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4012 + ... + 4251.

It is an arithmetic number, because the mean of its divisors is an integer number (92970).

2⁹⁹¹⁵⁶⁰ is an apocalyptic number.

It is an amenable number.

991560 is an abundant number, since it is smaller than the sum of its proper divisors (1983480).

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

991560 is a wasteful number, since it uses less digits than its factorization.

991560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8277 (or 8273 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 991560 is about 995.7710580249. The cubic root of 991560 is about 99.7178714500.

It can be divided in two parts, 991 and 560, that added together give a palindrome (1551).

The spelling of 991560 in words is "nine hundred ninety-one thousand, five hundred sixty".