21751120 has 40 divisors (see below), whose sum is σ = 51755616. Its totient is φ = 8496768.

The previous prime is 21751111. The next prime is 21751127. The reversal of 21751120 is 2115712.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×21751120² = 946222442508800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21751127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 279 + ... + 6601.

Almost surely, 2^21751120 is an apocalyptic number.

21751120 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 21751120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25877808).

21751120 is an abundant number, since it is smaller than the sum of its proper divisors (30004496).

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

21751120 is a wasteful number, since it uses less digits than its factorization.

21751120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6379 (or 6373 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21751120 is about 4663.8096016025. The cubic root of 21751120 is about 279.1432998437.

Adding to 21751120 its reverse (2115712), we get a palindrome (23866832).

The spelling of 21751120 in words is "twenty-one million, seven hundred fifty-one thousand, one hundred twenty".