513521521081 has 2 divisors, whose sum is σ = 513521521082. Its totient is φ = 513521521080.

The previous prime is 513521521031. The next prime is 513521521087. The reversal of 513521521081 is 180125125315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 454119645456 + 59401875625 = 673884^2 + 243725^2 .

It is a cyclic number.

It is not a de Polignac number, because 513521521081 - 2¹¹ = 513521519033 is a prime.

It is a super-2 number, since 2×513521521081² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (513521521087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 256760760540 + 256760760541.

It is an arithmetic number, because the mean of its divisors is an integer number (256760760541).

Almost surely, 2^513521521081 is an apocalyptic number.

It is an amenable number.

513521521081 is a deficient number, since it is larger than the sum of its proper divisors (1).

513521521081 is an equidigital number, since it uses as much as digits as its factorization.

513521521081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12000, while the sum is 34.

Adding to 513521521081 its reverse (180125125315), we get a palindrome (693646646396).

The spelling of 513521521081 in words is "five hundred thirteen billion, five hundred twenty-one million, five hundred twenty-one thousand, eighty-one".