20867221856 has 96 divisors (see below), whose sum is σ = 44758381248. Its totient is φ = 9519390720.

The previous prime is 20867221841. The next prime is 20867221867. The reversal of 20867221856 is 65812276802.

It is a self number, because there is not a number n which added to its sum of digits gives 20867221856.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16014101 + ... + 16015403.

It is an arithmetic number, because the mean of its divisors is an integer number (466233138).

Almost surely, 2^20867221856 is an apocalyptic number.

20867221856 is a gapful number since it is divisible by the number (26) 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 20867221856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22379190624).

20867221856 is an abundant number, since it is smaller than the sum of its proper divisors (23891159392).

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

20867221856 is a wasteful number, since it uses less digits than its factorization.

20867221856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1744 (or 1736 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 47.

The spelling of 20867221856 in words is "twenty billion, eight hundred sixty-seven million, two hundred twenty-one thousand, eight hundred fifty-six".