21041164656 has 120 divisors (see below), whose sum is σ = 62956015200. Its totient is φ = 6536982528.

The previous prime is 21041164637. The next prime is 21041164679. The reversal of 21041164656 is 65646114012.

21041164656 is a `hidden beast` number, since 2 + 1 + 0 + 4 + 1 + 1 + 646 + 5 + 6 = 666.

It is a super-2 number, since 2×21041164656² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21041164656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 210420 + ... + 293868.

It is an arithmetic number, because the mean of its divisors is an integer number (524633460).

Almost surely, 2^21041164656 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 21041164656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31478007600).

21041164656 is an abundant number, since it is smaller than the sum of its proper divisors (41914850544).

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

21041164656 is a wasteful number, since it uses less digits than its factorization.

21041164656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83583 (or 83574 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

Adding to 21041164656 its reverse (65646114012), we get a palindrome (86687278668).

The spelling of 21041164656 in words is "twenty-one billion, forty-one million, one hundred sixty-four thousand, six hundred fifty-six".