21504454241440 has 24 divisors (see below), whose sum is σ = 50804273145780. Its totient is φ = 8601781696512.

The previous prime is 21504454241437. The next prime is 21504454241449. The reversal of 21504454241440 is 4414245440512.

It can be written as a sum of positive squares in 2 ways, for example, as 20069432331664 + 1435021909776 = 4479892^2 + 1197924^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21504454241393 and 21504454241402.

It is not an unprimeable number, because it can be changed into a prime (21504454241449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67201419345 + ... + 67201419664.

Almost surely, 2^{21504454241440} is an apocalyptic number.

21504454241440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21504454241440 is an abundant number, since it is smaller than the sum of its proper divisors (29299818904340).

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

21504454241440 is a wasteful number, since it uses less digits than its factorization.

21504454241440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134402839024 (or 134402839016 counting only the distinct ones).

The product of its (nonzero) digits is 409600, while the sum is 40.

Adding to 21504454241440 its reverse (4414245440512), we get a palindrome (25918699681952).

The spelling of 21504454241440 in words is "twenty-one trillion, five hundred four billion, four hundred fifty-four million, two hundred forty-one thousand, four hundred forty".