129543921 has 16 divisors (see below), whose sum is σ = 206680320. Its totient is φ = 79719120.

The previous prime is 129543877. The next prime is 129543929. The reversal of 129543921 is 129345921.

129543921 is a `hidden beast` number, since 1 + 29 + 543 + 92 + 1 = 666.

It is not a de Polignac number, because 129543921 - 2⁷ = 129543793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129543929) 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 in 15 ways as a sum of consecutive naturals, for example, 184185 + ... + 184886.

It is an arithmetic number, because the mean of its divisors is an integer number (12917520).

Almost surely, 2^129543921 is an apocalyptic number.

It is an amenable number.

129543921 is a deficient number, since it is larger than the sum of its proper divisors (77136399).

129543921 is a wasteful number, since it uses less digits than its factorization.

129543921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369093 (or 369087 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 129543921 is about 11381.7362910937. The cubic root of 129543921 is about 505.9865965818.

The spelling of 129543921 in words is "one hundred twenty-nine million, five hundred forty-three thousand, nine hundred twenty-one".