21316533 has 8 divisors (see below), whose sum is σ = 32482368. Its totient is φ = 12180864.

The previous prime is 21316531. The next prime is 21316553. The reversal of 21316533 is 33561312.

It is a happy number.

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

It is not a de Polignac number, because 21316533 - 2¹ = 21316531 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 507516 + ... + 507557.

It is an arithmetic number, because the mean of its divisors is an integer number (4060296).

Almost surely, 2^21316533 is an apocalyptic number.

It is an amenable number.

21316533 is a deficient number, since it is larger than the sum of its proper divisors (11165835).

21316533 is a wasteful number, since it uses less digits than its factorization.

21316533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1015083.

The product of its digits is 1620, while the sum is 24.

The square root of 21316533 is about 4616.9831058820. The cubic root of 21316533 is about 277.2716862421.

Adding to 21316533 its reverse (33561312), we get a palindrome (54877845).

The spelling of 21316533 in words is "twenty-one million, three hundred sixteen thousand, five hundred thirty-three".