21333220 has 48 divisors (see below), whose sum is σ = 46267200. Its totient is φ = 8259200.

The previous prime is 21333199. The next prime is 21333251. The reversal of 21333220 is 2233312.

It is a junction number, because it is equal to n+sod(n) for n = 21333194 and 21333203.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119091 + ... + 119269.

It is an arithmetic number, because the mean of its divisors is an integer number (963900).

Almost surely, 2^21333220 is an apocalyptic number.

21333220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21333220 is an abundant number, since it is smaller than the sum of its proper divisors (24933980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21333220 is a wasteful number, since it uses less digits than its factorization.

21333220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348 (or 346 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 16.

The square root of 21333220 is about 4618.7898848075. The cubic root of 21333220 is about 277.3440186085.

Adding to 21333220 its reverse (2233312), we get a palindrome (23566532).

It can be divided in two parts, 213 and 33220, that added together give a palindrome (33433).

The spelling of 21333220 in words is "twenty-one million, three hundred thirty-three thousand, two hundred twenty".