20864287 has 8 divisors (see below), whose sum is σ = 22562496. Its totient is φ = 19218432.

The previous prime is 20864281. The next prime is 20864297. The reversal of 20864287 is 78246802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20864287 - 2¹¹ = 20862239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20864281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12258 + ... + 13855.

It is an arithmetic number, because the mean of its divisors is an integer number (2820312).

Almost surely, 2^20864287 is an apocalyptic number.

20864287 is a deficient number, since it is larger than the sum of its proper divisors (1698209).

20864287 is a wasteful number, since it uses less digits than its factorization.

20864287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26177.

The product of its (nonzero) digits is 43008, while the sum is 37.

The square root of 20864287 is about 4567.7441916114. The cubic root of 20864287 is about 275.2968123124.

The spelling of 20864287 in words is "twenty million, eight hundred sixty-four thousand, two hundred eighty-seven".