129924721 has 2 divisors, whose sum is σ = 129924722. Its totient is φ = 129924720.

The previous prime is 129924713. The next prime is 129924749. The reversal of 129924721 is 127429921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127238400 + 2686321 = 11280^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 129924721 - 2³ = 129924713 is a prime.

It is not a weakly prime, because it can be changed into another prime (129924701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64962360 + 64962361.

It is an arithmetic number, because the mean of its divisors is an integer number (64962361).

Almost surely, 2^129924721 is an apocalyptic number.

It is an amenable number.

129924721 is a deficient number, since it is larger than the sum of its proper divisors (1).

129924721 is an equidigital number, since it uses as much as digits as its factorization.

129924721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 129924721 is about 11398.4525704150. The cubic root of 129924721 is about 506.4819014571.

The spelling of 129924721 in words is "one hundred twenty-nine million, nine hundred twenty-four thousand, seven hundred twenty-one".