21144456 has 64 divisors (see below), whose sum is σ = 59875200. Its totient is φ = 6911424.

The previous prime is 21144437. The next prime is 21144467. The reversal of 21144456 is 65444112.

21144456 is a `hidden beast` number, since 211 + 4 + 445 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10525 + ... + 12371.

It is an arithmetic number, because the mean of its divisors is an integer number (935550).

Almost surely, 2^21144456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21144456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29937600).

21144456 is an abundant number, since it is smaller than the sum of its proper divisors (38730744).

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

21144456 is a wasteful number, since it uses less digits than its factorization.

21144456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1915 (or 1905 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21144456 is about 4598.3101243827. The cubic root of 21144456 is about 276.5235807917.

Adding to 21144456 its reverse (65444112), we get a palindrome (86588568).

The spelling of 21144456 in words is "twenty-one million, one hundred forty-four thousand, four hundred fifty-six".