21087286 has 16 divisors (see below), whose sum is σ = 35310528. Its totient is φ = 9361800.

The previous prime is 21087281. The next prime is 21087289. The reversal of 21087286 is 68278012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21087281) 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, 10200 + ... + 12091.

It is an arithmetic number, because the mean of its divisors is an integer number (2206908).

Almost surely, 2^21087286 is an apocalyptic number.

21087286 is a deficient number, since it is larger than the sum of its proper divisors (14223242).

21087286 is a wasteful number, since it uses less digits than its factorization.

21087286 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22347.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 21087286 is about 4592.0895026121. The cubic root of 21087286 is about 276.2741360128.

The spelling of 21087286 in words is "twenty-one million, eighty-seven thousand, two hundred eighty-six".