285991000 has 64 divisors (see below), whose sum is σ = 708626880. Its totient is φ = 107660800.

The previous prime is 285990973. The next prime is 285991003. The reversal of 285991000 is 199582.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285991003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8589 + ... + 25411.

It is an arithmetic number, because the mean of its divisors is an integer number (11072295).

Almost surely, 2^285991000 is an apocalyptic number.

285991000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 285991000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (354313440).

285991000 is an abundant number, since it is smaller than the sum of its proper divisors (422635880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

285991000 is a wasteful number, since it uses less digits than its factorization.

285991000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16861 (or 16847 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 285991000 is about 16911.2684326162. The cubic root of 285991000 is about 658.8463163325.

The spelling of 285991000 in words is "two hundred eighty-five million, nine hundred ninety-one thousand".