21368411064 has 768 divisors, whose sum is σ = 82188288000. Its totient is φ = 5022051840.

The previous prime is 21368411063. The next prime is 21368411083. The reversal of 21368411064 is 46011486312.

It is a super-2 number, since 2×21368411064² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368411063) by changing a digit.

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 191 ways as a sum of consecutive naturals, for example, 153729507 + ... + 153729645.

It is an arithmetic number, because the mean of its divisors is an integer number (107016000).

Almost surely, 2^21368411064 is an apocalyptic number.

21368411064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21368411064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41094144000).

21368411064 is an abundant number, since it is smaller than the sum of its proper divisors (60819876936).

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

21368411064 is a wasteful number, since it uses less digits than its factorization.

21368411064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270 (or 254 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

Adding to 21368411064 its reverse (46011486312), we get a palindrome (67379897376).

The spelling of 21368411064 in words is "twenty-one billion, three hundred sixty-eight million, four hundred eleven thousand, sixty-four".