21253212052605 has 192 divisors, whose sum is σ = 40809582777600. Its totient is φ = 10167684710400.

The previous prime is 21253212052603. The next prime is 21253212052613. The reversal of 21253212052605 is 50625021235212.

21253212052605 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 3 + 2 + 120 + 526 + 0 + 5 = 666.

It is not a de Polignac number, because 21253212052605 - 2¹ = 21253212052603 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21253212052605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253212052603) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2346083566 + ... + 2346092624.

It is an arithmetic number, because the mean of its divisors is an integer number (212549910300).

Almost surely, 2^{21253212052605} is an apocalyptic number.

It is an amenable number.

21253212052605 is a deficient number, since it is larger than the sum of its proper divisors (19556370724995).

21253212052605 is a wasteful number, since it uses less digits than its factorization.

21253212052605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9916 (or 9913 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

Adding to 21253212052605 its reverse (50625021235212), we get a palindrome (71878233287817).

The spelling of 21253212052605 in words is "twenty-one trillion, two hundred fifty-three billion, two hundred twelve million, fifty-two thousand, six hundred five".