1272129409 has 4 divisors (see below), whose sum is σ = 1282146304. Its totient is φ = 1262112516.

The previous prime is 1272129403. The next prime is 1272129437. The reversal of 1272129409 is 9049212721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9049212721 = 48413 ⋅186917.

It is a cyclic number.

It is not a de Polignac number, because 1272129409 - 2⁷ = 1272129281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1272129403) 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, 5008257 + ... + 5008510.

It is an arithmetic number, because the mean of its divisors is an integer number (320536576).

Almost surely, 2^1272129409 is an apocalyptic number.

It is an amenable number.

1272129409 is a deficient number, since it is larger than the sum of its proper divisors (10016895).

1272129409 is a wasteful number, since it uses less digits than its factorization.

1272129409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10016894.

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

The square root of 1272129409 is about 35666.9231782053. The cubic root of 1272129409 is about 1083.5370456411.

The spelling of 1272129409 in words is "one billion, two hundred seventy-two million, one hundred twenty-nine thousand, four hundred nine".