21978440000 has 420 divisors, whose sum is σ = 63320980800. Its totient is φ = 7539840000.

The previous prime is 21978439969. The next prime is 21978440101. The reversal of 21978440000 is 4487912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 91959881 + ... + 91960119.

It is an arithmetic number, because the mean of its divisors is an integer number (150764240).

Almost surely, 2^21978440000 is an apocalyptic number.

21978440000 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 21978440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31660490400).

21978440000 is an abundant number, since it is smaller than the sum of its proper divisors (41342540800).

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

21978440000 is a wasteful number, since it uses less digits than its factorization.

21978440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 276 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The spelling of 21978440000 in words is "twenty-one billion, nine hundred seventy-eight million, four hundred forty thousand".