129401009 has 2 divisors, whose sum is σ = 129401010. Its totient is φ = 129401008.

The previous prime is 129401003. The next prime is 129401029. The reversal of 129401009 is 900104921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67699984 + 61701025 = 8228^2 + 7855^2 .

It is an emirp because it is prime and its reverse (900104921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129401009 - 2¹² = 129396913 is a prime.

It is a super-2 number, since 2×129401009² = 33489242260436162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (129401003) 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 as a sum of consecutive naturals, namely, 64700504 + 64700505.

It is an arithmetic number, because the mean of its divisors is an integer number (64700505).

Almost surely, 2^129401009 is an apocalyptic number.

It is an amenable number.

129401009 is a deficient number, since it is larger than the sum of its proper divisors (1).

129401009 is an equidigital number, since it uses as much as digits as its factorization.

129401009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 129401009 is about 11375.4564304031. The cubic root of 129401009 is about 505.8004610909.

The spelling of 129401009 in words is "one hundred twenty-nine million, four hundred one thousand, nine".