21251120 has 160 divisors (see below), whose sum is σ = 59996160. Its totient is φ = 6912000.

The previous prime is 21251117. The next prime is 21251123. The reversal of 21251120 is 2115212.

It is an interprime number because it is at equal distance from previous prime (21251117) and next prime (21251123).

It is a super-2 number, since 2×21251120² = 903220202508800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21251095 and 21251104.

It is not an unprimeable number, because it can be changed into a prime (21251123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 518300 + ... + 518340.

It is an arithmetic number, because the mean of its divisors is an integer number (374976).

Almost surely, 2^21251120 is an apocalyptic number.

21251120 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 21251120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29998080).

21251120 is an abundant number, since it is smaller than the sum of its proper divisors (38745040).

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

21251120 is a wasteful number, since it uses less digits than its factorization.

21251120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21251120 is about 4609.8937081022. The cubic root of 21251120 is about 276.9877789618.

Adding to 21251120 its reverse (2115212), we get a palindrome (23366332).

The spelling of 21251120 in words is "twenty-one million, two hundred fifty-one thousand, one hundred twenty".