21731160 has 128 divisors (see below), whose sum is σ = 72264960. Its totient is φ = 5184000.

The previous prime is 21731147. The next prime is 21731161. The reversal of 21731160 is 6113712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731161) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 133239 + ... + 133401.

It is an arithmetic number, because the mean of its divisors is an integer number (564570).

Almost surely, 2^21731160 is an apocalyptic number.

21731160 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 21731160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36132480).

21731160 is an abundant number, since it is smaller than the sum of its proper divisors (50533800).

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

21731160 is a wasteful number, since it uses less digits than its factorization.

21731160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289 (or 285 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 21731160 is about 4661.6692289351. The cubic root of 21731160 is about 279.0578880667.

Adding to 21731160 its reverse (6113712), we get a palindrome (27844872).

It can be divided in two parts, 2173 and 1160, that added together give a palindrome (3333).

The spelling of 21731160 in words is "twenty-one million, seven hundred thirty-one thousand, one hundred sixty".