21333330 has 48 divisors (see below), whose sum is σ = 55724760. Its totient is φ = 5662464.

The previous prime is 21333329. The next prime is 21333353. The reversal of 21333330 is 3333312.

21333330 is a `hidden beast` number, since 2 + 1 + 333 + 330 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 21316689 + 16641 = 4617^2 + 129^2 .

It is a super-2 number, since 2×21333330² = 910221937777800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25966 + ... + 26774.

Almost surely, 2^21333330 is an apocalyptic number.

21333330 is an abundant number, since it is smaller than the sum of its proper divisors (34391430).

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

21333330 is a wasteful number, since it uses less digits than its factorization.

21333330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1115 (or 1112 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 18.

The square root of 21333330 is about 4618.8017926731. The cubic root of 21333330 is about 277.3444952952.

Subtracting from 21333330 its sum of digits (18), we obtain a palindrome (21333312).

Adding to 21333330 its reverse (3333312), we get a palindrome (24666642).

The spelling of 21333330 in words is "twenty-one million, three hundred thirty-three thousand, three hundred thirty".