21666532432 has 40 divisors (see below), whose sum is σ = 43525785600. Its totient is φ = 10435780992.

The previous prime is 21666532429. The next prime is 21666532549. The reversal of 21666532432 is 23423566612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150513 + ... + 256879.

It is an arithmetic number, because the mean of its divisors is an integer number (1088144640).

Almost surely, 2^21666532432 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 21666532432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21762892800).

21666532432 is an abundant number, since it is smaller than the sum of its proper divisors (21859253168).

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

21666532432 is a wasteful number, since it uses less digits than its factorization.

21666532432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106843 (or 106837 counting only the distinct ones).

The product of its digits is 311040, while the sum is 40.

The spelling of 21666532432 in words is "twenty-one billion, six hundred sixty-six million, five hundred thirty-two thousand, four hundred thirty-two".