129625921 has 2 divisors, whose sum is σ = 129625922. Its totient is φ = 129625920.

The previous prime is 129625897. The next prime is 129625927. The reversal of 129625921 is 129526921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104775696 + 24850225 = 10236^2 + 4985^2 .

It is an emirp because it is prime and its reverse (129526921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129625921 - 2¹¹ = 129623873 is a prime.

It is not a weakly prime, because it can be changed into another prime (129625927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64812960 + 64812961.

It is an arithmetic number, because the mean of its divisors is an integer number (64812961).

Almost surely, 2^129625921 is an apocalyptic number.

It is an amenable number.

129625921 is a deficient number, since it is larger than the sum of its proper divisors (1).

129625921 is an equidigital number, since it uses as much as digits as its factorization.

129625921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 37.

The square root of 129625921 is about 11385.3379835647. The cubic root of 129625921 is about 506.0933355402.

It can be divided in two parts, 1296 and 25921, that multiplied together give a square (33593616 = 5796²).

The spelling of 129625921 in words is "one hundred twenty-nine million, six hundred twenty-five thousand, nine hundred twenty-one".