21124456 has 16 divisors (see below), whose sum is σ = 39753540. Its totient is φ = 10523520.

The previous prime is 21124391. The next prime is 21124459. The reversal of 21124456 is 65442112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19660356 + 1464100 = 4434^2 + 1210^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21124456.

It is not an unprimeable number, because it can be changed into a prime (21124459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2451 + ... + 6946.

Almost surely, 2^21124456 is an apocalyptic number.

It is an amenable number.

21124456 is a deficient number, since it is larger than the sum of its proper divisors (18629084).

21124456 is a wasteful number, since it uses less digits than its factorization.

21124456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9684 (or 9680 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21124456 is about 4596.1348979333. The cubic root of 21124456 is about 276.4363677614.

Adding to 21124456 its reverse (65442112), we get a palindrome (86566568).

The spelling of 21124456 in words is "twenty-one million, one hundred twenty-four thousand, four hundred fifty-six".