21208545180 has 144 divisors (see below), whose sum is σ = 70663057920. Its totient is φ = 5124974976.

The previous prime is 21208545139. The next prime is 21208545187. The reversal of 21208545180 is 8154580212.

21208545180 is a `hidden beast` number, since 2 + 120 + 8 + 5 + 451 + 80 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21208545187) 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, 56152 + ... + 213471.

It is an arithmetic number, because the mean of its divisors is an integer number (490715680).

Almost surely, 2^21208545180 is an apocalyptic number.

21208545180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21208545180 is an abundant number, since it is smaller than the sum of its proper divisors (49454512740).

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

21208545180 is a wasteful number, since it uses less digits than its factorization.

21208545180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269680 (or 269675 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 36.

The spelling of 21208545180 in words is "twenty-one billion, two hundred eight million, five hundred forty-five thousand, one hundred eighty".