21868617 has 8 divisors (see below), whose sum is σ = 29237824. Its totient is φ = 14539248.

The previous prime is 21868603. The next prime is 21868619. The reversal of 21868617 is 71686812.

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

It is not a de Polignac number, because 21868617 - 2¹⁶ = 21803081 is a prime.

It is a super-3 number, since 3×21868617³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21868619) 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 7 ways as a sum of consecutive naturals, for example, 8653 + ... + 10890.

It is an arithmetic number, because the mean of its divisors is an integer number (3654728).

Almost surely, 2^21868617 is an apocalyptic number.

It is an amenable number.

21868617 is a deficient number, since it is larger than the sum of its proper divisors (7369207).

21868617 is a wasteful number, since it uses less digits than its factorization.

21868617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19919.

The product of its digits is 32256, while the sum is 39.

The square root of 21868617 is about 4676.3893122793. The cubic root of 21868617 is about 279.6450306207.

The spelling of 21868617 in words is "twenty-one million, eight hundred sixty-eight thousand, six hundred seventeen".