291240 has 48 divisors (see below), whose sum is σ = 947700. Its totient is φ = 77568.

The previous prime is 291217. The next prime is 291253. The reversal of 291240 is 42192.

It can be written as a sum of positive squares in 2 ways, for example, as 285156 + 6084 = 534^2 + 78^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

291240 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 11 ways as a sum of consecutive naturals, for example, 45 + ... + 764.

2²⁹¹²⁴⁰ is an apocalyptic number.

291240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 291240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (473850).

291240 is an abundant number, since it is smaller than the sum of its proper divisors (656460).

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

291240 is a wasteful number, since it uses less digits than its factorization.

291240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 291240 is about 539.6665637225. Note that the first 3 decimals coincide. The cubic root of 291240 is about 66.2852666155.

The spelling of 291240 in words is "two hundred ninety-one thousand, two hundred forty".