21554144 has 12 divisors (see below), whose sum is σ = 42434784. Its totient is φ = 10777056.

The previous prime is 21554111. The next prime is 21554149. The reversal of 21554144 is 44145512.

It is a super-2 number, since 2×21554144² = 929162247145472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554149) by changing a digit.

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 as a sum of consecutive naturals, namely, 336752 + ... + 336815.

It is an arithmetic number, because the mean of its divisors is an integer number (3536232).

Almost surely, 2^21554144 is an apocalyptic number.

It is an amenable number.

21554144 is a deficient number, since it is larger than the sum of its proper divisors (20880640).

21554144 is an equidigital number, since it uses as much as digits as its factorization.

21554144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673577 (or 673569 counting only the distinct ones).

The product of its digits is 3200, while the sum is 26.

The square root of 21554144 is about 4642.6440742318. The cubic root of 21554144 is about 278.2981119650.

Adding to 21554144 its reverse (44145512), we get a palindrome (65699656).

The spelling of 21554144 in words is "twenty-one million, five hundred fifty-four thousand, one hundred forty-four".