287391 has 8 divisors (see below), whose sum is σ = 412720. Its totient is φ = 176832.

The previous prime is 287387. The next prime is 287393. The reversal of 287391 is 193782.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 287391 - 2² = 287387 is a prime.

It is a Duffinian number.

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 287391.

It is not an unprimeable number, because it can be changed into a prime (287393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3646 + ... + 3723.

It is an arithmetic number, because the mean of its divisors is an integer number (51590).

2²⁸⁷³⁹¹ is an apocalyptic number.

287391 is a deficient number, since it is larger than the sum of its proper divisors (125329).

287391 is a wasteful number, since it uses less digits than its factorization.

287391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7385.

The product of its digits is 3024, while the sum is 30.

The square root of 287391 is about 536.0886120783. The cubic root of 287391 is about 65.9919641272.

The spelling of 287391 in words is "two hundred eighty-seven thousand, three hundred ninety-one".