21368361888 has 144 divisors (see below), whose sum is σ = 64698923016. Its totient is φ = 6666485760.

The previous prime is 21368361881. The next prime is 21368361901. The reversal of 21368361888 is 88816386312.

21368361888 is a `hidden beast` number, since 2 + 13 + 6 + 8 + 3 + 618 + 8 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 16458837264 + 4909524624 = 128292^2 + 70068^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21368361881) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 874120 + ... + 898232.

Almost surely, 2^21368361888 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 21368361888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32349461508).

21368361888 is an abundant number, since it is smaller than the sum of its proper divisors (43330561128).

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

21368361888 is a wasteful number, since it uses less digits than its factorization.

21368361888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24327 (or 24316 counting only the distinct ones).

The product of its digits is 2654208, while the sum is 54.

The spelling of 21368361888 in words is "twenty-one billion, three hundred sixty-eight million, three hundred sixty-one thousand, eight hundred eighty-eight".