21660004912 has 160 divisors (see below), whose sum is σ = 57068347392. Its totient is φ = 7713902592.

The previous prime is 21660004907. The next prime is 21660004913. The reversal of 21660004912 is 21940006612.

It is not an unprimeable number, because it can be changed into a prime (21660004913) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 550273 + ... + 588319.

Almost surely, 2^21660004912 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 21660004912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28534173696).

21660004912 is an abundant number, since it is smaller than the sum of its proper divisors (35408342480).

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

21660004912 is a wasteful number, since it uses less digits than its factorization.

21660004912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38115 (or 38109 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The spelling of 21660004912 in words is "twenty-one billion, six hundred sixty million, four thousand, nine hundred twelve".