21442556 has 6 divisors (see below), whose sum is σ = 37524480. Its totient is φ = 10721276.

The previous prime is 21442543. The next prime is 21442591. The reversal of 21442556 is 65524412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680316 + ... + 2680323.

It is an arithmetic number, because the mean of its divisors is an integer number (6254080).

Almost surely, 2^21442556 is an apocalyptic number.

It is an amenable number.

21442556 is a deficient number, since it is larger than the sum of its proper divisors (16081924).

21442556 is a wasteful number, since it uses less digits than its factorization.

21442556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5360643 (or 5360641 counting only the distinct ones).

The product of its digits is 9600, while the sum is 29.

The square root of 21442556 is about 4630.6107588524. The cubic root of 21442556 is about 277.8170215607.

Adding to 21442556 its reverse (65524412), we get a palindrome (86966968).

The spelling of 21442556 in words is "twenty-one million, four hundred forty-two thousand, five hundred fifty-six".