21108391528852 has 6 divisors (see below), whose sum is σ = 36939685175498. Its totient is φ = 10554195764424.

The previous prime is 21108391528843. The next prime is 21108391528871. The reversal of 21108391528852 is 25882519380112.

It can be written as a sum of positive squares in only one way, i.e., 20066493630096 + 1041897898756 = 4479564^2 + 1020734^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21108391528793 and 21108391528802.

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, 2638548941103 + ... + 2638548941110.

Almost surely, 2^{21108391528852} is an apocalyptic number.

It is an amenable number.

21108391528852 is a deficient number, since it is larger than the sum of its proper divisors (15831293646646).

21108391528852 is a wasteful number, since it uses less digits than its factorization.

21108391528852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5277097882217 (or 5277097882215 counting only the distinct ones).

The product of its (nonzero) digits is 2764800, while the sum is 55.

The spelling of 21108391528852 in words is "twenty-one trillion, one hundred eight billion, three hundred ninety-one million, five hundred twenty-eight thousand, eight hundred fifty-two".