21305353504450 has 24 divisors (see below), whose sum is σ = 39792388899780. Its totient is φ = 8486779814400.

The previous prime is 21305353504447. The next prime is 21305353504481. The reversal of 21305353504450 is 5440535350312.

It can be written as a sum of positive squares in 6 ways, for example, as 6740726956681 + 14564626547769 = 2596291^2 + 3816363^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 884027515 + ... + 884051614.

Almost surely, 2^{21305353504450} is an apocalyptic number.

21305353504450 is a deficient number, since it is larger than the sum of its proper divisors (18487035395330).

21305353504450 is a wasteful number, since it uses less digits than its factorization.

21305353504450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768079382 (or 1768079377 counting only the distinct ones).

The product of its (nonzero) digits is 540000, while the sum is 40.

Adding to 21305353504450 its reverse (5440535350312), we get a palindrome (26745888854762).

The spelling of 21305353504450 in words is "twenty-one trillion, three hundred five billion, three hundred fifty-three million, five hundred four thousand, four hundred fifty".