21585271104 has 168 divisors, whose sum is σ = 65289257280. Its totient is φ = 6804559872.

The previous prime is 21585271091. The next prime is 21585271109. The reversal of 21585271104 is 40117258512.

It is a happy number.

21585271104 is a `hidden beast` number, since 2 + 1 + 585 + 2 + 71 + 1 + 0 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21585271109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1169919 + ... + 1188225.

Almost surely, 2^21585271104 is an apocalyptic number.

21585271104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21585271104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32644628640).

21585271104 is an abundant number, since it is smaller than the sum of its proper divisors (43703986176).

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

21585271104 is a wasteful number, since it uses less digits than its factorization.

21585271104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18437 (or 18424 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The spelling of 21585271104 in words is "twenty-one billion, five hundred eighty-five million, two hundred seventy-one thousand, one hundred four".