21779856000 has 1536 divisors, whose sum is σ = 100085207040. Its totient is φ = 4423680000.

The previous prime is 21779855947. The next prime is 21779856001. The reversal of 21779856000 is 65897712.

21779856000 is a `hidden beast` number, since 2 + 17 + 79 + 8 + 560 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21779856001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 531215980 + ... + 531216020.

It is an arithmetic number, because the mean of its divisors is an integer number (65159640).

Almost surely, 2^21779856000 is an apocalyptic number.

21779856000 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 21779856000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50042603520).

21779856000 is an abundant number, since it is smaller than the sum of its proper divisors (78305351040).

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

21779856000 is a wasteful number, since it uses less digits than its factorization.

21779856000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 106 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 21779856000 in words is "twenty-one billion, seven hundred seventy-nine million, eight hundred fifty-six thousand".