231521540609 has 2 divisors, whose sum is σ = 231521540610. Its totient is φ = 231521540608.

The previous prime is 231521540561. The next prime is 231521540623. The reversal of 231521540609 is 906045125132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 228439070209 + 3082470400 = 477953^2 + 55520^2 .

It is a cyclic number.

It is not a de Polignac number, because 231521540609 - 2⁸ = 231521540353 is a prime.

It is not a weakly prime, because it can be changed into another prime (231521540909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115760770304 + 115760770305.

It is an arithmetic number, because the mean of its divisors is an integer number (115760770305).

Almost surely, 2^231521540609 is an apocalyptic number.

It is an amenable number.

231521540609 is a deficient number, since it is larger than the sum of its proper divisors (1).

231521540609 is an equidigital number, since it uses as much as digits as its factorization.

231521540609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 231521540609 in words is "two hundred thirty-one billion, five hundred twenty-one million, five hundred forty thousand, six hundred nine".