21540989180 has 24 divisors (see below), whose sum is σ = 46339398000. Its totient is φ = 8406239360.

The previous prime is 21540989179. The next prime is 21540989201. The reversal of 21540989180 is 8198904512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13133930 + ... + 13135569.

It is an arithmetic number, because the mean of its divisors is an integer number (1930808250).

Almost surely, 2^21540989180 is an apocalyptic number.

21540989180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21540989180 is an abundant number, since it is smaller than the sum of its proper divisors (24798408820).

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

21540989180 is a wasteful number, since it uses less digits than its factorization.

21540989180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26269549 (or 26269547 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 47.

The spelling of 21540989180 in words is "twenty-one billion, five hundred forty million, nine hundred eighty-nine thousand, one hundred eighty".