129554561 has 4 divisors (see below), whose sum is σ = 135187392. Its totient is φ = 123921732.

The previous prime is 129554543. The next prime is 129554587. The reversal of 129554561 is 165455921.

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, and also an emirpimes, since its reverse is a distinct semiprime: 165455921 = 163 ⋅1015067.

It is a cyclic number.

It is not a de Polignac number, because 129554561 - 2¹⁴ = 129538177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129553561) 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 in 3 ways as a sum of consecutive naturals, for example, 2816381 + ... + 2816426.

It is an arithmetic number, because the mean of its divisors is an integer number (33796848).

Almost surely, 2^129554561 is an apocalyptic number.

It is an amenable number.

129554561 is a deficient number, since it is larger than the sum of its proper divisors (5632831).

129554561 is an equidigital number, since it uses as much as digits as its factorization.

129554561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5632830.

The product of its digits is 54000, while the sum is 38.

The square root of 129554561 is about 11382.2036970000. The cubic root of 129554561 is about 506.0004491552. Note that the first 3 decimals are identical.

The spelling of 129554561 in words is "one hundred twenty-nine million, five hundred fifty-four thousand, five hundred sixty-one".