287640591 has 16 divisors (see below), whose sum is σ = 438950400. Its totient is φ = 164125728.

The previous prime is 287640571. The next prime is 287640607. The reversal of 287640591 is 195046782.

It is not a de Polignac number, because 287640591 - 2¹⁵ = 287607823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287640541) 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, 5230 + ... + 24548.

It is an arithmetic number, because the mean of its divisors is an integer number (27434400).

Almost surely, 2^287640591 is an apocalyptic number.

287640591 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

287640591 is a deficient number, since it is larger than the sum of its proper divisors (151309809).

287640591 is a wasteful number, since it uses less digits than its factorization.

287640591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20038.

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 287640591 is about 16959.9702535116. The cubic root of 287640591 is about 660.1106265434.

The spelling of 287640591 in words is "two hundred eighty-seven million, six hundred forty thousand, five hundred ninety-one".