129271409 has 4 divisors (see below), whose sum is σ = 129510900. Its totient is φ = 129031920.

The previous prime is 129271397. The next prime is 129271423. The reversal of 129271409 is 904172921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904172921 = 1879 ⋅481199.

It can be written as a sum of positive squares in 2 ways, for example, as 24720784 + 104550625 = 4972^2 + 10225^2 .

It is a cyclic number.

It is not a de Polignac number, because 129271409 - 2¹⁶ = 129205873 is a prime.

It is a super-2 number, since 2×129271409² = 33422194369690562, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (129270409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118934 + ... + 120015.

It is an arithmetic number, because the mean of its divisors is an integer number (32377725).

Almost surely, 2^129271409 is an apocalyptic number.

It is an amenable number.

129271409 is a deficient number, since it is larger than the sum of its proper divisors (239491).

129271409 is an equidigital number, since it uses as much as digits as its factorization.

129271409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239490.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 129271409 is about 11369.7585286584. The cubic root of 129271409 is about 505.6315452619.

The spelling of 129271409 in words is "one hundred twenty-nine million, two hundred seventy-one thousand, four hundred nine".