285981 has 4 divisors (see below), whose sum is σ = 381312. Its totient is φ = 190652.

The previous prime is 285979. The next prime is 285983. The reversal of 285981 is 189582.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (285979) and next prime (285983).

It is a cyclic number.

It is not a de Polignac number, because 285981 - 2¹ = 285979 is a prime.

It is a super-2 number, since 2×285981² = 163570264722, which contains 22 as substring.

It is a D-number.

285981 is a lucky 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 285981.

It is not an unprimeable number, because it can be changed into a prime (285983) 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, 47661 + ... + 47666.

It is an arithmetic number, because the mean of its divisors is an integer number (95328).

2²⁸⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

285981 is a deficient number, since it is larger than the sum of its proper divisors (95331).

285981 is an equidigital number, since it uses as much as digits as its factorization.

285981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95330.

The product of its digits is 5760, while the sum is 33.

The square root of 285981 is about 534.7719139970. The cubic root of 285981 is about 65.8838637140.

The spelling of 285981 in words is "two hundred eighty-five thousand, nine hundred eighty-one".