21360686388 has 96 divisors (see below), whose sum is σ = 56493158400. Its totient is φ = 6241015296.

The previous prime is 21360686363. The next prime is 21360686393. The reversal of 21360686388 is 88368606312.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 21360686388.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 181981 + ... + 275387.

It is an arithmetic number, because the mean of its divisors is an integer number (588470400).

Almost surely, 2^21360686388 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 21360686388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28246579200).

21360686388 is an abundant number, since it is smaller than the sum of its proper divisors (35132472012).

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

21360686388 is a wasteful number, since it uses less digits than its factorization.

21360686388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93509 (or 93507 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 51.

The spelling of 21360686388 in words is "twenty-one billion, three hundred sixty million, six hundred eighty-six thousand, three hundred eighty-eight".