21335868180 has 240 divisors, whose sum is σ = 73164700224. Its totient is φ = 5161812480.

The previous prime is 21335868161. The next prime is 21335868181. The reversal of 21335868180 is 8186853312.

21335868180 is a `hidden beast` number, since 21 + 33 + 586 + 8 + 18 + 0 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21335868181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 12170184 + ... + 12171936.

Almost surely, 2^21335868180 is an apocalyptic number.

21335868180 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 21335868180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36582350112).

21335868180 is an abundant number, since it is smaller than the sum of its proper divisors (51828832044).

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

21335868180 is a wasteful number, since it uses less digits than its factorization.

21335868180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2468 (or 2457 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 21335868180 in words is "twenty-one billion, three hundred thirty-five million, eight hundred sixty-eight thousand, one hundred eighty".