136131581 has 2 divisors, whose sum is σ = 136131582. Its totient is φ = 136131580.

The previous prime is 136131559. The next prime is 136131623. The reversal of 136131581 is 185131631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98505625 + 37625956 = 9925^2 + 6134^2 .

It is a cyclic number.

It is not a de Polignac number, because 136131581 - 2¹⁰ = 136130557 is a prime.

It is a super-2 number, since 2×136131581² = 37063614691119122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_7705703 and since 136131581 and 7705703 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (136131511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68065790 + 68065791.

It is an arithmetic number, because the mean of its divisors is an integer number (68065791).

Almost surely, 2^136131581 is an apocalyptic number.

It is an amenable number.

136131581 is a deficient number, since it is larger than the sum of its proper divisors (1).

136131581 is an equidigital number, since it uses as much as digits as its factorization.

136131581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 29.

The square root of 136131581 is about 11667.5439146377. The cubic root of 136131581 is about 514.4221135967.

Subtracting 136131581 from its reverse (185131631), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 136131581 in words is "one hundred thirty-six million, one hundred thirty-one thousand, five hundred eighty-one".