21366109981440 has 1152 divisors, whose sum is σ = 89558391767040. Its totient is φ = 4720243507200.

The previous prime is 21366109981423. The next prime is 21366109981441. The reversal of 21366109981440 is 4418990166312.

21366109981440 is a `hidden beast` number, since 2 + 1 + 3 + 6 + 6 + 109 + 98 + 1 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21366109981441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 9126914670 + ... + 9126917010.

It is an arithmetic number, because the mean of its divisors is an integer number (77741659520).

Almost surely, 2^{21366109981440} is an apocalyptic number.

21366109981440 is a gapful number since it is divisible by the number (20) 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 21366109981440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44779195883520).

21366109981440 is an abundant number, since it is smaller than the sum of its proper divisors (68192281785600).

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

21366109981440 is a wasteful number, since it uses less digits than its factorization.

21366109981440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3626 (or 3606 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The spelling of 21366109981440 in words is "twenty-one trillion, three hundred sixty-six billion, one hundred nine million, nine hundred eighty-one thousand, four hundred forty".