21865733 has 4 divisors (see below), whose sum is σ = 22278348. Its totient is φ = 21453120.

The previous prime is 21865721. The next prime is 21865741. The reversal of 21865733 is 33756812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17447329 + 4418404 = 4177^2 + 2102^2 .

It is a cyclic number.

It is not a de Polignac number, because 21865733 - 2¹⁶ = 21800197 is a prime.

It is a super-2 number, since 2×21865733² = 956220559254578, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21865693 and 21865702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21865783) 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 3 ways as a sum of consecutive naturals, for example, 206228 + ... + 206333.

It is an arithmetic number, because the mean of its divisors is an integer number (5569587).

Almost surely, 2^21865733 is an apocalyptic number.

It is an amenable number.

21865733 is a deficient number, since it is larger than the sum of its proper divisors (412615).

21865733 is an equidigital number, since it uses as much as digits as its factorization.

21865733 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412614.

The product of its digits is 30240, while the sum is 35.

The square root of 21865733 is about 4676.0809445518. The cubic root of 21865733 is about 279.6327370263.

The spelling of 21865733 in words is "twenty-one million, eight hundred sixty-five thousand, seven hundred thirty-three".