21744142 has 32 divisors (see below), whose sum is σ = 39384000. Its totient is φ = 8989344.

The previous prime is 21744137. The next prime is 21744143. The reversal of 21744142 is 24144712.

It is a super-2 number, since 2×21744142² = 945615422632328, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21744143) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19348 + ... + 20440.

It is an arithmetic number, because the mean of its divisors is an integer number (1230750).

Almost surely, 2^21744142 is an apocalyptic number.

21744142 is a deficient number, since it is larger than the sum of its proper divisors (17639858).

21744142 is a wasteful number, since it uses less digits than its factorization.

21744142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1145 (or 1131 counting only the distinct ones).

The product of its digits is 1792, while the sum is 25.

The square root of 21744142 is about 4663.0614407275. The cubic root of 21744142 is about 279.1134458977.

Adding to 21744142 its reverse (24144712), we get a palindrome (45888854).

The spelling of 21744142 in words is "twenty-one million, seven hundred forty-four thousand, one hundred forty-two".