285991389 has 12 divisors (see below), whose sum is σ = 424263996. Its totient is φ = 185507712.

The previous prime is 285991373. The next prime is 285991393. The reversal of 285991389 is 983199582.

It can be written as a sum of positive squares in 2 ways, for example, as 122279364 + 163712025 = 11058^2 + 12795^2 .

It is not a de Polignac number, because 285991389 - 2⁴ = 285991373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285991319) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 429084 + ... + 429749.

It is an arithmetic number, because the mean of its divisors is an integer number (35355333).

Almost surely, 2^285991389 is an apocalyptic number.

It is an amenable number.

285991389 is a deficient number, since it is larger than the sum of its proper divisors (138272607).

285991389 is a wasteful number, since it uses less digits than its factorization.

285991389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 858876 (or 858873 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 54.

The square root of 285991389 is about 16911.2799338193. The cubic root of 285991389 is about 658.8466150494.

The spelling of 285991389 in words is "two hundred eighty-five million, nine hundred ninety-one thousand, three hundred eighty-nine".