21836217 has 32 divisors (see below), whose sum is σ = 33264000. Its totient is φ = 12644352.

The previous prime is 21836209. The next prime is 21836219. The reversal of 21836217 is 71263812.

It is not a de Polignac number, because 21836217 - 2³ = 21836209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21836219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48409 + ... + 48857.

It is an arithmetic number, because the mean of its divisors is an integer number (1039500).

Almost surely, 2^21836217 is an apocalyptic number.

It is an amenable number.

21836217 is a deficient number, since it is larger than the sum of its proper divisors (11427783).

21836217 is a wasteful number, since it uses less digits than its factorization.

21836217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537.

The product of its digits is 4032, while the sum is 30.

The square root of 21836217 is about 4672.9238170550. The cubic root of 21836217 is about 279.5068573154.

The spelling of 21836217 in words is "twenty-one million, eight hundred thirty-six thousand, two hundred seventeen".