21271441536 has 128 divisors (see below), whose sum is σ = 64945440000. Its totient is φ = 6845948928.

The previous prime is 21271441531. The next prime is 21271441553. The reversal of 21271441536 is 63514417212.

21271441536 is a `hidden beast` number, since 2 + 12 + 71 + 4 + 41 + 536 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21271441536.

It is not an unprimeable number, because it can be changed into a prime (21271441531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5896 + ... + 206343.

It is an arithmetic number, because the mean of its divisors is an integer number (507386250).

Almost surely, 2^21271441536 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 21271441536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32472720000).

21271441536 is an abundant number, since it is smaller than the sum of its proper divisors (43673998464).

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

21271441536 is a wasteful number, since it uses less digits than its factorization.

21271441536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212291 (or 212273 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

Adding to 21271441536 its reverse (63514417212), we get a palindrome (84785858748).

The spelling of 21271441536 in words is "twenty-one billion, two hundred seventy-one million, four hundred forty-one thousand, five hundred thirty-six".