287681 has 2 divisors, whose sum is σ = 287682. Its totient is φ = 287680.

The previous prime is 287671. The next prime is 287689. The reversal of 287681 is 186782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207025 + 80656 = 455^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 287681 - 2¹⁸ = 25537 is a prime.

It is a super-2 number, since 2×287681² = 165520715522, which contains 22 as substring.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 287681.

It is not a weakly prime, because it can be changed into another prime (287689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 143840 + 143841.

It is an arithmetic number, because the mean of its divisors is an integer number (143841).

287681 is a Friedman number, since it can be written as 88^2+6^7+1, using all its digits and the basic arithmetic operations.

2²⁸⁷⁶⁸¹ is an apocalyptic number.

It is an amenable number.

287681 is a deficient number, since it is larger than the sum of its proper divisors (1).

287681 is an equidigital number, since it uses as much as digits as its factorization.

287681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 32.

The square root of 287681 is about 536.3590215518. The cubic root of 287681 is about 66.0141536832.

The spelling of 287681 in words is "two hundred eighty-seven thousand, six hundred eighty-one".