285305881 has 27 divisors (see below), whose sum is σ = 353053269. Its totient is φ = 229852728.

The previous prime is 285305821. The next prime is 285305897. The reversal of 285305881 is 188503582.

The square root of 285305881 is 16891.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 285305881 - 2⁷ = 285305753 is a prime.

It is a super-3 number, since 3×285305881³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (285305821) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2246440 + ... + 2246566.

It is an arithmetic number, because the mean of its divisors is an integer number (13076047).

Almost surely, 2^285305881 is an apocalyptic number.

285305881 is the 16891-st square number.

285305881 is the 8446-th centered octagonal number.

It is an amenable number.

285305881 is a deficient number, since it is larger than the sum of its proper divisors (67747388).

285305881 is an equidigital number, since it uses as much as digits as its factorization.

285305881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 40.

The cubic root of 285305881 is about 658.3197857099.

The spelling of 285305881 in words is "two hundred eighty-five million, three hundred five thousand, eight hundred eighty-one".