21752120 has 64 divisors (see below), whose sum is σ = 53676000. Its totient is φ = 7884288.

The previous prime is 21752113. The next prime is 21752141. The reversal of 21752120 is 2125712.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21752092 and 21752101.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30326 + ... + 31034.

Almost surely, 2^21752120 is an apocalyptic number.

21752120 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 21752120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26838000).

21752120 is an abundant number, since it is smaller than the sum of its proper divisors (31923880).

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

21752120 is a wasteful number, since it uses less digits than its factorization.

21752120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792 (or 788 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21752120 is about 4663.9168088636. The cubic root of 21752120 is about 279.1475776161.

Adding to 21752120 its reverse (2125712), we get a palindrome (23877832).

The spelling of 21752120 in words is "twenty-one million, seven hundred fifty-two thousand, one hundred twenty".