21345541304440 has 16 divisors (see below), whose sum is σ = 48027467935080. Its totient is φ = 8538216521760.

The previous prime is 21345541304411. The next prime is 21345541304443. The reversal of 21345541304440 is 4440314554312.

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 533638532611 = 21345541304440 / (2 + 1 + 3 + 4 + 5 + 5 + 4 + 1 + 3 + 0 + 4 + 4 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 21345541304393 and 21345541304402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345541304443) 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, 266819266266 + ... + 266819266345.

Almost surely, 2^{21345541304440} is an apocalyptic number.

21345541304440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21345541304440 is an abundant number, since it is smaller than the sum of its proper divisors (26681926630640).

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

21345541304440 is a wasteful number, since it uses less digits than its factorization.

21345541304440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533638532622 (or 533638532618 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 40.

Adding to 21345541304440 its reverse (4440314554312), we get a palindrome (25785855858752).

The spelling of 21345541304440 in words is "twenty-one trillion, three hundred forty-five billion, five hundred forty-one million, three hundred four thousand, four hundred forty".