21545135513252 has 24 divisors (see below), whose sum is σ = 40605874281336. Its totient is φ = 9943521654528.

The previous prime is 21545135513227. The next prime is 21545135513261. The reversal of 21545135513252 is 25231553154512.

It can be written as a sum of positive squares in 4 ways, for example, as 1030903131556 + 20514232381696 = 1015334^2 + 4529264^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6712433 + ... + 9388664.

It is an arithmetic number, because the mean of its divisors is an integer number (1691911428389).

Almost surely, 2^{21545135513252} is an apocalyptic number.

It is an amenable number.

21545135513252 is a deficient number, since it is larger than the sum of its proper divisors (19060738768084).

21545135513252 is a wasteful number, since it uses less digits than its factorization.

21545135513252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16126847 (or 16126845 counting only the distinct ones).

The product of its digits is 900000, while the sum is 44.

Adding to 21545135513252 its reverse (25231553154512), we get a palindrome (46776688667764).

The spelling of 21545135513252 in words is "twenty-one trillion, five hundred forty-five billion, one hundred thirty-five million, five hundred thirteen thousand, two hundred fifty-two".