21180163356 has 144 divisors (see below), whose sum is σ = 60385468416. Its totient is φ = 6201360000.

The previous prime is 21180163351. The next prime is 21180163397. The reversal of 21180163356 is 65336108112.

21180163356 is a `hidden beast` number, since 2 + 1 + 18 + 0 + 1 + 633 + 5 + 6 = 666.

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 21180163356.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180163351) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12164646 + ... + 12166386.

Almost surely, 2^21180163356 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 21180163356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30192734208).

21180163356 is an abundant number, since it is smaller than the sum of its proper divisors (39205305060).

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

21180163356 is a wasteful number, since it uses less digits than its factorization.

21180163356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2784 (or 2779 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21180163356 in words is "twenty-one billion, one hundred eighty million, one hundred sixty-three thousand, three hundred fifty-six".