21171120 has 80 divisors (see below), whose sum is σ = 69504480. Its totient is φ = 5312512.

The previous prime is 21171119. The next prime is 21171133. The reversal of 21171120 is 2117112.

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

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 21171120.

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, 1486 + ... + 6674.

It is an arithmetic number, because the mean of its divisors is an integer number (868806).

Almost surely, 2^21171120 is an apocalyptic number.

21171120 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 21171120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34752240).

21171120 is an abundant number, since it is smaller than the sum of its proper divisors (48333360).

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

21171120 is a wasteful number, since it uses less digits than its factorization.

21171120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5222 (or 5216 counting only the distinct ones).

The product of its (nonzero) digits is 28, while the sum is 15.

The square root of 21171120 is about 4601.2085368955. The cubic root of 21171120 is about 276.6397677111.

Adding to 21171120 its reverse (2117112), we get a palindrome (23288232).

The spelling of 21171120 in words is "twenty-one million, one hundred seventy-one thousand, one hundred twenty".