21631144 has 16 divisors (see below), whose sum is σ = 41130720. Its totient is φ = 10662960.

The previous prime is 21631121. The next prime is 21631171. The reversal of 21631144 is 44113612.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18474 + ... + 19609.

It is an arithmetic number, because the mean of its divisors is an integer number (2570670).

Almost surely, 2^21631144 is an apocalyptic number.

It is an amenable number.

21631144 is a deficient number, since it is larger than the sum of its proper divisors (19499576).

21631144 is a wasteful number, since it uses less digits than its factorization.

21631144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38160 (or 38156 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

The square root of 21631144 is about 4650.9293694917. The cubic root of 21631144 is about 278.6291154069.

Adding to 21631144 its reverse (44113612), we get a palindrome (65744756).

The spelling of 21631144 in words is "twenty-one million, six hundred thirty-one thousand, one hundred forty-four".