21686233 has 8 divisors (see below), whose sum is σ = 22284416. Its totient is φ = 21092400.

The previous prime is 21686227. The next prime is 21686243. The reversal of 21686233 is 33268612.

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

It is a cyclic number.

It is not a de Polignac number, because 21686233 - 2⁹ = 21685721 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21686195 and 21686204.

It is not an unprimeable number, because it can be changed into a prime (21686243) 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, 10723 + ... + 12583.

It is an arithmetic number, because the mean of its divisors is an integer number (2785552).

Almost surely, 2^21686233 is an apocalyptic number.

It is an amenable number.

21686233 is a deficient number, since it is larger than the sum of its proper divisors (598183).

21686233 is a wasteful number, since it uses less digits than its factorization.

21686233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175.

The product of its digits is 10368, while the sum is 31.

The square root of 21686233 is about 4656.8479683150. The cubic root of 21686233 is about 278.8654472965.

The spelling of 21686233 in words is "twenty-one million, six hundred eighty-six thousand, two hundred thirty-three".