21330510 has 16 divisors (see below), whose sum is σ = 51193296. Its totient is φ = 5688128.

The previous prime is 21330503. The next prime is 21330581. The reversal of 21330510 is 1503312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21330510.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 355479 + ... + 355538.

It is an arithmetic number, because the mean of its divisors is an integer number (3199581).

Almost surely, 2^21330510 is an apocalyptic number.

21330510 is an abundant number, since it is smaller than the sum of its proper divisors (29862786).

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

21330510 is a wasteful number, since it uses less digits than its factorization.

21330510 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711027.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21330510 is about 4618.4965086054. The cubic root of 21330510 is about 277.3322742630.

Adding to 21330510 its reverse (1503312), we get a palindrome (22833822).

The spelling of 21330510 in words is "twenty-one million, three hundred thirty thousand, five hundred ten".