156131561 has 2 divisors, whose sum is σ = 156131562. Its totient is φ = 156131560.

The previous prime is 156131539. The next prime is 156131629. The reversal of 156131561 is 165131651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115885225 + 40246336 = 10765^2 + 6344^2 .

It is a cyclic number.

It is not a de Polignac number, because 156131561 - 2¹⁴ = 156115177 is a prime.

It is not a weakly prime, because it can be changed into another prime (156131161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78065780 + 78065781.

It is an arithmetic number, because the mean of its divisors is an integer number (78065781).

Almost surely, 2^156131561 is an apocalyptic number.

It is an amenable number.

156131561 is a deficient number, since it is larger than the sum of its proper divisors (1).

156131561 is an equidigital number, since it uses as much as digits as its factorization.

156131561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2700, while the sum is 29.

The square root of 156131561 is about 12495.2615418806. The cubic root of 156131561 is about 538.4725479261.

The spelling of 156131561 in words is "one hundred fifty-six million, one hundred thirty-one thousand, five hundred sixty-one".