21361526324640 has 288 divisors, whose sum is σ = 73826680099536. Its totient is φ = 5624016076800.

The previous prime is 21361526324573. The next prime is 21361526324641. The reversal of 21361526324640 is 4642362516312.

21361526324640 is a `hidden beast` number, since 2 + 1 + 3 + 6 + 1 + 5 + 2 + 632 + 4 + 6 + 4 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 15190256811024 + 6171269513616 = 3897468^2 + 2484204^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×21361526324640² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21361526324641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51132282 + ... + 51548358.

Almost surely, 2^{21361526324640} is an apocalyptic number.

21361526324640 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 21361526324640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36913340049768).

21361526324640 is an abundant number, since it is smaller than the sum of its proper divisors (52465153774896).

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

21361526324640 is a wasteful number, since it uses less digits than its factorization.

21361526324640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416552 (or 416541 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 21361526324640 in words is "twenty-one trillion, three hundred sixty-one billion, five hundred twenty-six million, three hundred twenty-four thousand, six hundred forty".