21318099552 has 144 divisors (see below), whose sum is σ = 64267454160. Its totient is φ = 6679904256.

The previous prime is 21318099521. The next prime is 21318099577. The reversal of 21318099552 is 25599081312.

21318099552 is a `hidden beast` number, since 2 + 1 + 3 + 1 + 8 + 0 + 99 + 552 = 666.

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

It is a super-2 number, since 2×21318099552² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21318099498 and 21318099507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4986888 + ... + 4991160.

It is an arithmetic number, because the mean of its divisors is an integer number (446301765).

Almost surely, 2^21318099552 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 21318099552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32133727080).

21318099552 is an abundant number, since it is smaller than the sum of its proper divisors (42949354608).

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

21318099552 is a wasteful number, since it uses less digits than its factorization.

21318099552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5325 (or 5314 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The spelling of 21318099552 in words is "twenty-one billion, three hundred eighteen million, ninety-nine thousand, five hundred fifty-two".