21980315500 has 144 divisors (see below), whose sum is σ = 56826780192. Its totient is φ = 7377744000.

The previous prime is 21980315491. The next prime is 21980315579. The reversal of 21980315500 is 551308912.

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 47 ways as a sum of consecutive naturals, for example, 772527 + ... + 800473.

It is an arithmetic number, because the mean of its divisors is an integer number (394630418).

Almost surely, 2^21980315500 is an apocalyptic number.

21980315500 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 21980315500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28413390096).

21980315500 is an abundant number, since it is smaller than the sum of its proper divisors (34846464692).

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

21980315500 is a wasteful number, since it uses less digits than its factorization.

21980315500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28001 (or 27978 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 21980315500 in words is "twenty-one billion, nine hundred eighty million, three hundred fifteen thousand, five hundred".