131609521 has 2 divisors, whose sum is σ = 131609522. Its totient is φ = 131609520.

The previous prime is 131609483. The next prime is 131609557. The reversal of 131609521 is 125906131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122965921 + 8643600 = 11089^2 + 2940^2 .

It is a cyclic number.

It is not a de Polignac number, because 131609521 - 2¹⁷ = 131478449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 131609521.

It is not a weakly prime, because it can be changed into another prime (131609581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65804760 + 65804761.

It is an arithmetic number, because the mean of its divisors is an integer number (65804761).

Almost surely, 2^131609521 is an apocalyptic number.

It is an amenable number.

131609521 is a deficient number, since it is larger than the sum of its proper divisors (1).

131609521 is an equidigital number, since it uses as much as digits as its factorization.

131609521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 131609521 is about 11472.1192898261. The cubic root of 131609521 is about 508.6617754760.

The spelling of 131609521 in words is "one hundred thirty-one million, six hundred nine thousand, five hundred twenty-one".