291440 has 20 divisors (see below), whose sum is σ = 677784. Its totient is φ = 116544.

The previous prime is 291439. The next prime is 291443. The reversal of 291440 is 44192.

291440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

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 291440.

It is not an unprimeable number, because it can be changed into a prime (291443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1742 + ... + 1901.

2²⁹¹⁴⁴⁰ is an apocalyptic number.

291440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

291440 is an abundant number, since it is smaller than the sum of its proper divisors (386344).

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

291440 is a wasteful number, since it uses less digits than its factorization.

291440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3656 (or 3650 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 291440 is about 539.8518315242. The cubic root of 291440 is about 66.3004362578.

The spelling of 291440 in words is "two hundred ninety-one thousand, four hundred forty".