21289390980 has 288 divisors, whose sum is σ = 70991714304. Its totient is φ = 4735104000.

The previous prime is 21289390951. The next prime is 21289390981. The reversal of 21289390980 is 8909398212.

It is not an unprimeable number, because it can be changed into a prime (21289390981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 18025990 + ... + 18027170.

It is an arithmetic number, because the mean of its divisors is an integer number (246499008).

Almost surely, 2^21289390980 is an apocalyptic number.

21289390980 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 21289390980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35495857152).

21289390980 is an abundant number, since it is smaller than the sum of its proper divisors (49702323324).

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

21289390980 is a wasteful number, since it uses less digits than its factorization.

21289390980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1419 (or 1406 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 51.

The spelling of 21289390980 in words is "twenty-one billion, two hundred eighty-nine million, three hundred ninety thousand, nine hundred eighty".