21084880 has 20 divisors (see below), whose sum is σ = 49022532. Its totient is φ = 8433920.

The previous prime is 21084853. The next prime is 21084881. The reversal of 21084880 is 8848012.

It can be written as a sum of positive squares in 2 ways, for example, as 6431296 + 14653584 = 2536^2 + 3828^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×21084880² = 889144329228800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21084881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131701 + ... + 131860.

Almost surely, 2^21084880 is an apocalyptic number.

21084880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21084880 is an abundant number, since it is smaller than the sum of its proper divisors (27937652).

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

21084880 is a wasteful number, since it uses less digits than its factorization.

21084880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263574 (or 263568 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 21084880 is about 4591.8275228933. The cubic root of 21084880 is about 276.2636282460.

The spelling of 21084880 in words is "twenty-one million, eighty-four thousand, eight hundred eighty".