13531520221 has 2 divisors, whose sum is σ = 13531520222. Its totient is φ = 13531520220.

The previous prime is 13531520159. The next prime is 13531520237. The reversal of 13531520221 is 12202513531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7795124100 + 5736396121 = 88290^2 + 75739^2 .

It is a cyclic number.

It is not a de Polignac number, because 13531520221 - 2⁹ = 13531519709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13531520521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6765760110 + 6765760111.

It is an arithmetic number, because the mean of its divisors is an integer number (6765760111).

Almost surely, 2^13531520221 is an apocalyptic number.

It is an amenable number.

13531520221 is a deficient number, since it is larger than the sum of its proper divisors (1).

13531520221 is an equidigital number, since it uses as much as digits as its factorization.

13531520221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 25.

The spelling of 13531520221 in words is "thirteen billion, five hundred thirty-one million, five hundred twenty thousand, two hundred twenty-one".