21006663232 has 56 divisors (see below), whose sum is σ = 43526390976. Its totient is φ = 10039991808.

The previous prime is 21006663221. The next prime is 21006663259. The reversal of 21006663232 is 23236660012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21006663194 and 21006663203.

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 7 ways as a sum of consecutive naturals, for example, 2759143 + ... + 2766745.

Almost surely, 2^21006663232 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 21006663232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21763195488).

21006663232 is an abundant number, since it is smaller than the sum of its proper divisors (22519727744).

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

21006663232 is a wasteful number, since it uses less digits than its factorization.

21006663232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9515 (or 9505 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 31.

The spelling of 21006663232 in words is "twenty-one billion, six million, six hundred sixty-three thousand, two hundred thirty-two".