129289921 has 2 divisors, whose sum is σ = 129289922. Its totient is φ = 129289920.

The previous prime is 129289891. The next prime is 129289931. The reversal of 129289921 is 129982921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119049921 + 10240000 = 10911^2 + 3200^2 .

It is a cyclic number.

It is not a de Polignac number, because 129289921 - 2⁹ = 129289409 is a prime.

It is not a weakly prime, because it can be changed into another prime (129289931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64644960 + 64644961.

It is an arithmetic number, because the mean of its divisors is an integer number (64644961).

Almost surely, 2^129289921 is an apocalyptic number.

It is an amenable number.

129289921 is a deficient number, since it is larger than the sum of its proper divisors (1).

129289921 is an equidigital number, since it uses as much as digits as its factorization.

129289921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 43.

The square root of 129289921 is about 11370.5725889244. The cubic root of 129289921 is about 505.6556800247.

The spelling of 129289921 in words is "one hundred twenty-nine million, two hundred eighty-nine thousand, nine hundred twenty-one".