21215481336 has 512 divisors, whose sum is σ = 72938188800. Its totient is φ = 5583790080.

The previous prime is 21215481277. The next prime is 21215481337. The reversal of 21215481336 is 63318451212.

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 21215481336.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215481337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 154857460 + ... + 154857596.

It is an arithmetic number, because the mean of its divisors is an integer number (142457400).

Almost surely, 2^21215481336 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 21215481336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36469094400).

21215481336 is an abundant number, since it is smaller than the sum of its proper divisors (51722707464).

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

21215481336 is a wasteful number, since it uses less digits than its factorization.

21215481336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 306 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The spelling of 21215481336 in words is "twenty-one billion, two hundred fifteen million, four hundred eighty-one thousand, three hundred thirty-six".