21125553244 has 6 divisors (see below), whose sum is σ = 36969718184. Its totient is φ = 10562776620.

The previous prime is 21125553209. The next prime is 21125553259. The reversal of 21125553244 is 44235552112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640694152 + ... + 2640694159.

Almost surely, 2^21125553244 is an apocalyptic number.

It is an amenable number.

21125553244 is a deficient number, since it is larger than the sum of its proper divisors (15844164940).

21125553244 is a wasteful number, since it uses less digits than its factorization.

21125553244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5281388315 (or 5281388313 counting only the distinct ones).

The product of its digits is 48000, while the sum is 34.

The spelling of 21125553244 in words is "twenty-one billion, one hundred twenty-five million, five hundred fifty-three thousand, two hundred forty-four".