21686286 has 32 divisors (see below), whose sum is σ = 45577728. Its totient is φ = 6865760.

The previous prime is 21686281. The next prime is 21686299. The reversal of 21686286 is 68268612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21686281) 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, 22576 + ... + 23516.

It is an arithmetic number, because the mean of its divisors is an integer number (1424304).

Almost surely, 2^21686286 is an apocalyptic number.

21686286 is an abundant number, since it is smaller than the sum of its proper divisors (23891442).

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

21686286 is a wasteful number, since it uses less digits than its factorization.

21686286 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136.

The product of its digits is 55296, while the sum is 39.

The square root of 21686286 is about 4656.8536588559. The cubic root of 21686286 is about 278.8656744738.

The spelling of 21686286 in words is "twenty-one million, six hundred eighty-six thousand, two hundred eighty-six".