21330020 has 24 divisors (see below), whose sum is σ = 45084984. Its totient is φ = 8476416.

The previous prime is 21329999. The next prime is 21330047. The reversal of 21330020 is 2003312.

It can be written as a sum of positive squares in 4 ways, for example, as 4096 + 21325924 = 64^2 + 4618^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21329983 and 21330010.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (1878541).

Almost surely, 2^21330020 is an apocalyptic number.

21330020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21330020 is an abundant number, since it is smaller than the sum of its proper divisors (23754964).

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

21330020 is a wasteful number, since it uses less digits than its factorization.

21330020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6959 (or 6957 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 21330020 is about 4618.4434607344. The cubic root of 21330020 is about 277.3301506405.

Adding to 21330020 its reverse (2003312), we get a palindrome (23333332).

The spelling of 21330020 in words is "twenty-one million, three hundred thirty thousand, twenty".