129577561 has 4 divisors (see below), whose sum is σ = 135211392. Its totient is φ = 123943732.

The previous prime is 129577559. The next prime is 129577579. The reversal of 129577561 is 165775921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 129577561 - 2¹ = 129577559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129577501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2816881 + ... + 2816926.

It is an arithmetic number, because the mean of its divisors is an integer number (33802848).

Almost surely, 2^129577561 is an apocalyptic number.

It is an amenable number.

129577561 is a deficient number, since it is larger than the sum of its proper divisors (5633831).

129577561 is an equidigital number, since it uses as much as digits as its factorization.

129577561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5633830.

The product of its digits is 132300, while the sum is 43.

The square root of 129577561 is about 11383.2140013267. The cubic root of 129577561 is about 506.0303910361.

The spelling of 129577561 in words is "one hundred twenty-nine million, five hundred seventy-seven thousand, five hundred sixty-one".