21281080 has 16 divisors (see below), whose sum is σ = 47882520. Its totient is φ = 8512416.

The previous prime is 21281077. The next prime is 21281089. The reversal of 21281080 is 8018212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21281089) 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, 265974 + ... + 266053.

Almost surely, 2^21281080 is an apocalyptic number.

21281080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21281080 is an abundant number, since it is smaller than the sum of its proper divisors (26601440).

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

21281080 is a wasteful number, since it uses less digits than its factorization.

21281080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532038 (or 532034 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 21281080 is about 4613.1420962290. The cubic root of 21281080 is about 277.1178843731.

Adding to 21281080 its reverse (8018212), we get a palindrome (29299292).

The spelling of 21281080 in words is "twenty-one million, two hundred eighty-one thousand, eighty".