21086880 has 96 divisors (see below), whose sum is σ = 67060224. Its totient is φ = 5569536.

The previous prime is 21086861. The next prime is 21086887. The reversal of 21086880 is 8868012.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (21086887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94449 + ... + 94671.

It is an arithmetic number, because the mean of its divisors is an integer number (698544).

Almost surely, 2^21086880 is an apocalyptic number.

21086880 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 21086880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33530112).

21086880 is an abundant number, since it is smaller than the sum of its proper divisors (45973344).

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

21086880 is a wasteful number, since it uses less digits than its factorization.

21086880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 21086880 is about 4592.0452959438. The cubic root of 21086880 is about 276.2723629378.

The spelling of 21086880 in words is "twenty-one million, eighty-six thousand, eight hundred eighty".