21750120 has 240 divisors, whose sum is σ = 85660740. Its totient is φ = 4935168.

The previous prime is 21750119. The next prime is 21750133. The reversal of 21750120 is 2105712.

It can be written as a sum of positive squares in 2 ways, for example, as 21734244 + 15876 = 4662^2 + 126^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21750093 and 21750102.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 158692 + ... + 158828.

Almost surely, 2^21750120 is an apocalyptic number.

21750120 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 21750120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42830370).

21750120 is an abundant number, since it is smaller than the sum of its proper divisors (63910620).

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

21750120 is a wasteful number, since it uses less digits than its factorization.

21750120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21750120 is about 4663.7023918771. The cubic root of 21750120 is about 279.1390219402.

Adding to 21750120 its reverse (2105712), we get a palindrome (23855832).

The spelling of 21750120 in words is "twenty-one million, seven hundred fifty thousand, one hundred twenty".