21333505 has 8 divisors (see below), whose sum is σ = 25641792. Its totient is φ = 17039088.

The previous prime is 21333491. The next prime is 21333509. The reversal of 21333505 is 50533312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21333505 - 2¹³ = 21325313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21333509) 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, 292 + ... + 6538.

It is an arithmetic number, because the mean of its divisors is an integer number (3205224).

Almost surely, 2^21333505 is an apocalyptic number.

It is an amenable number.

21333505 is a deficient number, since it is larger than the sum of its proper divisors (4308287).

21333505 is an equidigital number, since it uses as much as digits as its factorization.

21333505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6935.

The product of its (nonzero) digits is 1350, while the sum is 22.

The square root of 21333505 is about 4618.8207369414. The cubic root of 21333505 is about 277.3452536571.

Adding to 21333505 its reverse (50533312), we get a palindrome (71866817).

The spelling of 21333505 in words is "twenty-one million, three hundred thirty-three thousand, five hundred five".