21416533 has 4 divisors (see below), whose sum is σ = 21637420. Its totient is φ = 21195648.

The previous prime is 21416531. The next prime is 21416539. The reversal of 21416533 is 33561412.

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 13704804 + 7711729 = 3702^2 + 2777^2 .

It is a cyclic number.

It is not a de Polignac number, because 21416533 - 2¹ = 21416531 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21416498 and 21416507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21416531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110298 + ... + 110491.

It is an arithmetic number, because the mean of its divisors is an integer number (5409355).

Almost surely, 2^21416533 is an apocalyptic number.

It is an amenable number.

21416533 is a deficient number, since it is larger than the sum of its proper divisors (220887).

21416533 is an equidigital number, since it uses as much as digits as its factorization.

21416533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220886.

The product of its digits is 2160, while the sum is 25.

The square root of 21416533 is about 4627.8000172868. The cubic root of 21416533 is about 277.7045884628.

Adding to 21416533 its reverse (33561412), we get a palindrome (54977945).

The spelling of 21416533 in words is "twenty-one million, four hundred sixteen thousand, five hundred thirty-three".