21120019980 has 48 divisors (see below), whose sum is σ = 59143392000. Its totient is φ = 5631306688.

The previous prime is 21120019961. The next prime is 21120020029. The reversal of 21120019980 is 8991002112.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 623521 + ... + 656519.

It is an arithmetic number, because the mean of its divisors is an integer number (1232154000).

Almost surely, 2^21120019980 is an apocalyptic number.

21120019980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120019980 is an abundant number, since it is smaller than the sum of its proper divisors (38023372020).

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

21120019980 is a wasteful number, since it uses less digits than its factorization.

21120019980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43678 (or 43676 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 33.

The spelling of 21120019980 in words is "twenty-one billion, one hundred twenty million, nineteen thousand, nine hundred eighty".