287228991 has 32 divisors (see below), whose sum is σ = 483591168. Its totient is φ = 147755520.

The previous prime is 287228989. The next prime is 287229001. The reversal of 287228991 is 199822782.

It is not a de Polignac number, because 287228991 - 2¹ = 287228989 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 287228991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287228941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9280 + ... + 25701.

It is an arithmetic number, because the mean of its divisors is an integer number (15112224).

Almost surely, 2^287228991 is an apocalyptic number.

287228991 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

287228991 is a deficient number, since it is larger than the sum of its proper divisors (196362177).

287228991 is a wasteful number, since it uses less digits than its factorization.

287228991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35031.

The product of its digits is 290304, while the sum is 48.

The square root of 287228991 is about 16947.8314542009. The cubic root of 287228991 is about 659.7956139399.

The spelling of 287228991 in words is "two hundred eighty-seven million, two hundred twenty-eight thousand, nine hundred ninety-one".