21308120 has 96 divisors (see below), whose sum is σ = 53751600. Its totient is φ = 7577856.

The previous prime is 21308107. The next prime is 21308137. The reversal of 21308120 is 2180312.

It is a congruent number.

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, 402014 + ... + 402066.

Almost surely, 2^21308120 is an apocalyptic number.

21308120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21308120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26875800).

21308120 is an abundant number, since it is smaller than the sum of its proper divisors (32443480).

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

21308120 is a wasteful number, since it uses less digits than its factorization.

21308120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21308120 is about 4616.0719231832. The cubic root of 21308120 is about 277.2352044864.

Adding to 21308120 its reverse (2180312), we get a palindrome (23488432).

The spelling of 21308120 in words is "twenty-one million, three hundred eight thousand, one hundred twenty".