131656409 has 2 divisors, whose sum is σ = 131656410. Its totient is φ = 131656408.

The previous prime is 131656391. The next prime is 131656463. The reversal of 131656409 is 904656131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112296409 + 19360000 = 10597^2 + 4400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131656409 is a prime.

It is not a weakly prime, because it can be changed into another prime (131656489) 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, 65828204 + 65828205.

It is an arithmetic number, because the mean of its divisors is an integer number (65828205).

Almost surely, 2^131656409 is an apocalyptic number.

It is an amenable number.

131656409 is a deficient number, since it is larger than the sum of its proper divisors (1).

131656409 is an equidigital number, since it uses as much as digits as its factorization.

131656409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 131656409 is about 11474.1626709752. The cubic root of 131656409 is about 508.7221746056.

The spelling of 131656409 in words is "one hundred thirty-one million, six hundred fifty-six thousand, four hundred nine".