21305181184 has 132 divisors (see below), whose sum is σ = 52459345116. Its totient is φ = 8593342464.

The previous prime is 21305181077. The next prime is 21305181211. The reversal of 21305181184 is 48118150312.

It can be written as a sum of positive squares in 2 ways, for example, as 6943555584 + 14361625600 = 83328^2 + 119840^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 840504 + ... + 865480.

Almost surely, 2^21305181184 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 21305181184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26229672558).

21305181184 is an abundant number, since it is smaller than the sum of its proper divisors (31154163932).

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

21305181184 is a wasteful number, since it uses less digits than its factorization.

21305181184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25028 (or 25003 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 34.

The spelling of 21305181184 in words is "twenty-one billion, three hundred five million, one hundred eighty-one thousand, one hundred eighty-four".