21144244 has 24 divisors (see below), whose sum is σ = 41132448. Its totient is φ = 9428640.

The previous prime is 21144229. The next prime is 21144259. The reversal of 21144244 is 44244112.

It is an interprime number because it is at equal distance from previous prime (21144229) and next prime (21144259).

It is a Harshad number since it is a multiple of its sum of digits (22).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2202 + ... + 6865.

It is an arithmetic number, because the mean of its divisors is an integer number (1713852).

Almost surely, 2^21144244 is an apocalyptic number.

It is an amenable number.

21144244 is a deficient number, since it is larger than the sum of its proper divisors (19988204).

21144244 is a wasteful number, since it uses less digits than its factorization.

21144244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9135 (or 9133 counting only the distinct ones).

The product of its digits is 1024, while the sum is 22.

The square root of 21144244 is about 4598.2870723781. The cubic root of 21144244 is about 276.5226566220.

Adding to 21144244 its reverse (44244112), we get a palindrome (65388356).

The spelling of 21144244 in words is "twenty-one million, one hundred forty-four thousand, two hundred forty-four".