21653144 has 16 divisors (see below), whose sum is σ = 40687920. Its totient is φ = 10803040.

The previous prime is 21653131. The next prime is 21653153. The reversal of 21653144 is 44135612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1334 + ... + 6714.

It is an arithmetic number, because the mean of its divisors is an integer number (2542995).

Almost surely, 2^21653144 is an apocalyptic number.

It is an amenable number.

21653144 is a deficient number, since it is larger than the sum of its proper divisors (19034776).

21653144 is a wasteful number, since it uses less digits than its factorization.

21653144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5890 (or 5886 counting only the distinct ones).

The product of its digits is 2880, while the sum is 26.

The square root of 21653144 is about 4653.2938871298. The cubic root of 21653144 is about 278.7235435085.

Adding to 21653144 its reverse (44135612), we get a palindrome (65788756).

The spelling of 21653144 in words is "twenty-one million, six hundred fifty-three thousand, one hundred forty-four".