21103280 has 40 divisors (see below), whose sum is σ = 53527824. Its totient is φ = 7673600.

The previous prime is 21103267. The next prime is 21103301. The reversal of 21103280 is 8230112.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11111 + ... + 12870.

Almost surely, 2^21103280 is an apocalyptic number.

21103280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21103280 is an abundant number, since it is smaller than the sum of its proper divisors (32424544).

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

21103280 is a wasteful number, since it uses less digits than its factorization.

21103280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24005 (or 23999 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21103280 is about 4593.8306455506. The cubic root of 21103280 is about 276.3439665867.

Adding to 21103280 its reverse (8230112), we get a palindrome (29333392).

It can be divided in two parts, 211032 and 80, that added together give a palindrome (211112).

The spelling of 21103280 in words is "twenty-one million, one hundred three thousand, two hundred eighty".