21383353872 has 120 divisors (see below), whose sum is σ = 61277149440. Its totient is φ = 6957849600.

The previous prime is 21383353861. The next prime is 21383353889. The reversal of 21383353872 is 27835338312.

21383353872 is a `hidden beast` number, since 2 + 13 + 8 + 33 + 538 + 72 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2710029 + ... + 2717907.

It is an arithmetic number, because the mean of its divisors is an integer number (510642912).

Almost surely, 2^21383353872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21383353872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30638574720).

21383353872 is an abundant number, since it is smaller than the sum of its proper divisors (39893795568).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21383353872 is a wasteful number, since it uses less digits than its factorization.

21383353872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8341 (or 8332 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The spelling of 21383353872 in words is "twenty-one billion, three hundred eighty-three million, three hundred fifty-three thousand, eight hundred seventy-two".