21663354264660 has 144 divisors (see below), whose sum is σ = 67340950290432. Its totient is φ = 5633814412800.

The previous prime is 21663354264653. The next prime is 21663354264707. The reversal of 21663354264660 is 6646245336612.

21663354264660 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 33 + 542 + 6 + 4 + 6 + 60 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21663354264597 and 21663354264606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18555117 + ... + 19688043.

It is an arithmetic number, because the mean of its divisors is an integer number (467645488128).

Almost surely, 2^{21663354264660} is an apocalyptic number.

21663354264660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21663354264660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33670475145216).

21663354264660 is an abundant number, since it is smaller than the sum of its proper divisors (45677596025772).

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

21663354264660 is a wasteful number, since it uses less digits than its factorization.

21663354264660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1135574 (or 1135569 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 54.

The spelling of 21663354264660 in words is "twenty-one trillion, six hundred sixty-three billion, three hundred fifty-four million, two hundred sixty-four thousand, six hundred sixty".