21855081468 has 144 divisors (see below), whose sum is σ = 58037676032. Its totient is φ = 6389539200.

The previous prime is 21855081467. The next prime is 21855081497. The reversal of 21855081468 is 86418055812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21855081467) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21920346 + ... + 21921342.

Almost surely, 2^21855081468 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 21855081468, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29018838016).

21855081468 is an abundant number, since it is smaller than the sum of its proper divisors (36182594564).

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

21855081468 is a wasteful number, since it uses less digits than its factorization.

21855081468 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1544 (or 1531 counting only the distinct ones).

The product of its (nonzero) digits is 614400, while the sum is 48.

The spelling of 21855081468 in words is "twenty-one billion, eight hundred fifty-five million, eighty-one thousand, four hundred sixty-eight".