21102320 has 80 divisors (see below), whose sum is σ = 51806208. Its totient is φ = 7983360.

The previous prime is 21102313. The next prime is 21102377. The reversal of 21102320 is 2320112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166097 + ... + 166223.

Almost surely, 2^21102320 is an apocalyptic number.

21102320 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 21102320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25903104).

21102320 is an abundant number, since it is smaller than the sum of its proper divisors (30703888).

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

21102320 is a wasteful number, since it uses less digits than its factorization.

21102320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 232 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21102320 is about 4593.7261564007. The cubic root of 21102320 is about 276.3397761760.

Adding to 21102320 its reverse (2320112), we get a palindrome (23422432).

The spelling of 21102320 in words is "twenty-one million, one hundred two thousand, three hundred twenty".