21581480466 has 96 divisors (see below), whose sum is σ = 57884037120. Its totient is φ = 5658844032.

The previous prime is 21581480441. The next prime is 21581480491. The reversal of 21581480466 is 66408418512.

It is a happy number.

21581480466 is a `hidden beast` number, since 2 + 1 + 581 + 4 + 8 + 0 + 4 + 66 = 666.

It is an interprime number because it is at equal distance from previous prime (21581480441) and next prime (21581480491).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 245295 + ... + 321453.

It is an arithmetic number, because the mean of its divisors is an integer number (602958720).

Almost surely, 2^21581480466 is an apocalyptic number.

21581480466 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21581480466, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28942018560).

21581480466 is an abundant number, since it is smaller than the sum of its proper divisors (36302556654).

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

21581480466 is a wasteful number, since it uses less digits than its factorization.

21581480466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76360 (or 76357 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

Adding to 21581480466 its reverse (66408418512), we get a palindrome (87989898978).

The spelling of 21581480466 in words is "twenty-one billion, five hundred eighty-one million, four hundred eighty thousand, four hundred sixty-six".