21878168780 has 144 divisors (see below), whose sum is σ = 52240204800. Its totient is φ = 7682837760.

The previous prime is 21878168779. The next prime is 21878168801. The reversal of 21878168780 is 8786187812.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6180251 + ... + 6183789.

It is an arithmetic number, because the mean of its divisors is an integer number (362779200).

Almost surely, 2^21878168780 is an apocalyptic number.

21878168780 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 21878168780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26120102400).

21878168780 is an abundant number, since it is smaller than the sum of its proper divisors (30362036020).

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

21878168780 is a wasteful number, since it uses less digits than its factorization.

21878168780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3664 (or 3649 counting only the distinct ones).

The product of its (nonzero) digits is 2408448, while the sum is 56.

The spelling of 21878168780 in words is "twenty-one billion, eight hundred seventy-eight million, one hundred sixty-eight thousand, seven hundred eighty".