21862556856 has 128 divisors (see below), whose sum is σ = 70382822400. Its totient is φ = 6158436480.

The previous prime is 21862556851. The next prime is 21862556893. The reversal of 21862556856 is 65865526812.

It is a happy number.

21862556856 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 2 + 556 + 85 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21862556851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5526 + ... + 209178.

It is an arithmetic number, because the mean of its divisors is an integer number (549865800).

Almost surely, 2^21862556856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21862556856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35191411200).

21862556856 is an abundant number, since it is smaller than the sum of its proper divisors (48520265544).

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

21862556856 is a wasteful number, since it uses less digits than its factorization.

21862556856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203746 (or 203736 counting only the distinct ones).

The product of its digits is 6912000, while the sum is 54.

The spelling of 21862556856 in words is "twenty-one billion, eight hundred sixty-two million, five hundred fifty-six thousand, eight hundred fifty-six".