21153330 has 96 divisors (see below), whose sum is σ = 62674560. Its totient is φ = 4899840.

The previous prime is 21153323. The next prime is 21153347. The reversal of 21153330 is 3335112.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22306 + ... + 23234.

It is an arithmetic number, because the mean of its divisors is an integer number (652860).

Almost surely, 2^21153330 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21153330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31337280).

21153330 is an abundant number, since it is smaller than the sum of its proper divisors (41521230).

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

21153330 is a wasteful number, since it uses less digits than its factorization.

21153330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 976 (or 973 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 18.

The square root of 21153330 is about 4599.2749428578. The cubic root of 21153330 is about 276.5622595995.

Adding to 21153330 its reverse (3335112), we get a palindrome (24488442).

It can be divided in two parts, 2115 and 3330, that added together give a palindrome (5445).

The spelling of 21153330 in words is "twenty-one million, one hundred fifty-three thousand, three hundred thirty".