21106880 has 56 divisors (see below), whose sum is σ = 51023520. Its totient is φ = 8314880.

The previous prime is 21106873. The next prime is 21106907. The reversal of 21106880 is 8860112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22256 + ... + 23184.

Almost surely, 2^21106880 is an apocalyptic number.

21106880 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 21106880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25511760).

21106880 is an abundant number, since it is smaller than the sum of its proper divisors (29916640).

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

21106880 is an equidigital number, since it uses as much as digits as its factorization.

21106880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1017 (or 1007 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 21106880 is about 4594.2224586974. Note that the first 3 decimals coincide. The cubic root of 21106880 is about 276.3596794951.

Adding to 21106880 its reverse (8860112), we get a palindrome (29966992).

The spelling of 21106880 in words is "twenty-one million, one hundred six thousand, eight hundred eighty".