21112144 has 10 divisors (see below), whose sum is σ = 40904810. Its totient is φ = 10556064.

The previous prime is 21112141. The next prime is 21112151. The reversal of 21112144 is 44121112.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13046544 + 8065600 = 3612^2 + 2840^2 .

It is a Harshad number since it is a multiple of its sum of digits (16), and also a Moran number because the ratio is a prime number: 1319509 = 21112144 / (2 + 1 + 1 + 1 + 2 + 1 + 4 + 4).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659739 + ... + 659770.

It is an arithmetic number, because the mean of its divisors is an integer number (4090481).

Almost surely, 2^21112144 is an apocalyptic number.

It is an amenable number.

21112144 is a deficient number, since it is larger than the sum of its proper divisors (19792666).

21112144 is a wasteful number, since it uses less digits than its factorization.

21112144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319517 (or 1319511 counting only the distinct ones).

The product of its digits is 64, while the sum is 16.

The square root of 21112144 is about 4594.7953164423. The cubic root of 21112144 is about 276.3826520429.

Adding to 21112144 its reverse (44121112), we get a palindrome (65233256).

The spelling of 21112144 in words is "twenty-one million, one hundred twelve thousand, one hundred forty-four".