1205513521 has 2 divisors, whose sum is σ = 1205513522. Its totient is φ = 1205513520.

The previous prime is 1205513509. The next prime is 1205513527. The reversal of 1205513521 is 1253155021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1032722496 + 172791025 = 32136^2 + 13145^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205513521 - 2¹¹ = 1205511473 is a prime.

It is not a weakly prime, because it can be changed into another prime (1205513527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602756760 + 602756761.

It is an arithmetic number, because the mean of its divisors is an integer number (602756761).

Almost surely, 2^1205513521 is an apocalyptic number.

It is an amenable number.

1205513521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205513521 is an equidigital number, since it uses as much as digits as its factorization.

1205513521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 1205513521 is about 34720.5057710858. The cubic root of 1205513521 is about 1064.2835802746.

Adding to 1205513521 its reverse (1253155021), we get a palindrome (2458668542).

The spelling of 1205513521 in words is "one billion, two hundred five million, five hundred thirteen thousand, five hundred twenty-one".