21280124 has 12 divisors (see below), whose sum is σ = 39430944. Its totient is φ = 10014144.

The previous prime is 21280117. The next prime is 21280153. The reversal of 21280124 is 42108212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21280096 and 21280105.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156404 + ... + 156539.

It is an arithmetic number, because the mean of its divisors is an integer number (3285912).

Almost surely, 2^21280124 is an apocalyptic number.

It is an amenable number.

21280124 is a deficient number, since it is larger than the sum of its proper divisors (18150820).

21280124 is a wasteful number, since it uses less digits than its factorization.

21280124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312964 (or 312962 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21280124 is about 4613.0384780533. The cubic root of 21280124 is about 277.1137346986.

Adding to 21280124 its reverse (42108212), we get a palindrome (63388336).

The spelling of 21280124 in words is "twenty-one million, two hundred eighty thousand, one hundred twenty-four".