291391 has 4 divisors (see below), whose sum is σ = 292984. Its totient is φ = 289800.

The previous prime is 291377. The next prime is 291419. The reversal of 291391 is 193192.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 291391 - 2⁵ = 291359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 480 + ... + 901.

It is an arithmetic number, because the mean of its divisors is an integer number (73246).

2²⁹¹³⁹¹ is an apocalyptic number.

291391 is a deficient number, since it is larger than the sum of its proper divisors (1593).

291391 is a wasteful number, since it uses less digits than its factorization.

291391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1592.

The product of its digits is 486, while the sum is 25.

The square root of 291391 is about 539.8064467937. The cubic root of 291391 is about 66.2967203375.

The spelling of 291391 in words is "two hundred ninety-one thousand, three hundred ninety-one".