21286233 has 20 divisors (see below), whose sum is σ = 31936740. Its totient is φ = 14128992.

The previous prime is 21286229. The next prime is 21286241. The reversal of 21286233 is 33268212.

It can be written as a sum of positive squares in 2 ways, for example, as 5817744 + 15468489 = 2412^2 + 3933^2 .

It is not a de Polignac number, because 21286233 - 2² = 21286229 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21286197 and 21286206.

It is not an unprimeable number, because it can be changed into a prime (21286273) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25263 + ... + 26091.

It is an arithmetic number, because the mean of its divisors is an integer number (1596837).

Almost surely, 2^21286233 is an apocalyptic number.

It is an amenable number.

21286233 is a deficient number, since it is larger than the sum of its proper divisors (10650507).

21286233 is an equidigital number, since it uses as much as digits as its factorization.

21286233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1158 (or 1149 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21286233 is about 4613.7005754600. The cubic root of 21286233 is about 277.1402496731.

The spelling of 21286233 in words is "twenty-one million, two hundred eighty-six thousand, two hundred thirty-three".