21520553544244 has 12 divisors (see below), whose sum is σ = 37804166303904. Its totient is φ = 10719363171704.

The previous prime is 21520553544241. The next prime is 21520553544247. The reversal of 21520553544244 is 44244535502512.

It is an interprime number because it is at equal distance from previous prime (21520553544241) and next prime (21520553544247).

It is a junction number, because it is equal to n+sod(n) for n = 21520553544194 and 21520553544203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520553544241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10228398922 + ... + 10228401025.

It is an arithmetic number, because the mean of its divisors is an integer number (3150347191992).

Almost surely, 2^{21520553544244} is an apocalyptic number.

It is an amenable number.

21520553544244 is a deficient number, since it is larger than the sum of its proper divisors (16283612759660).

21520553544244 is a wasteful number, since it uses less digits than its factorization.

21520553544244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20456800214 (or 20456800212 counting only the distinct ones).

The product of its (nonzero) digits is 3840000, while the sum is 46.

The spelling of 21520553544244 in words is "twenty-one trillion, five hundred twenty billion, five hundred fifty-three million, five hundred forty-four thousand, two hundred forty-four".