129601561 has 2 divisors, whose sum is σ = 129601562. Its totient is φ = 129601560.

The previous prime is 129601559. The next prime is 129601597. The reversal of 129601561 is 165106921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 128391561 + 1210000 = 11331^2 + 1100^2 .

It is a cyclic number.

It is not a de Polignac number, because 129601561 - 2¹ = 129601559 is a prime.

It is a super-2 number, since 2×129601561² = 33593129227273442, which contains 22 as substring.

Together with 129601559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (129601531) 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, 64800780 + 64800781.

It is an arithmetic number, because the mean of its divisors is an integer number (64800781).

Almost surely, 2^129601561 is an apocalyptic number.

It is an amenable number.

129601561 is a deficient number, since it is larger than the sum of its proper divisors (1).

129601561 is an equidigital number, since it uses as much as digits as its factorization.

129601561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 129601561 is about 11384.2681363362. The cubic root of 129601561 is about 506.0616309605.

The spelling of 129601561 in words is "one hundred twenty-nine million, six hundred one thousand, five hundred sixty-one".