127137809 has 4 divisors (see below), whose sum is σ = 130574004. Its totient is φ = 123701616.

The previous prime is 127137763. The next prime is 127137811. The reversal of 127137809 is 908731721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908731721 = 2341 ⋅388181.

It can be written as a sum of positive squares in 2 ways, for example, as 103469584 + 23668225 = 10172^2 + 4865^2 .

It is a cyclic number.

It is not a de Polignac number, because 127137809 - 2⁸ = 127137553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (127137889) 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, 1718042 + ... + 1718115.

It is an arithmetic number, because the mean of its divisors is an integer number (32643501).

Almost surely, 2^127137809 is an apocalyptic number.

It is an amenable number.

127137809 is a deficient number, since it is larger than the sum of its proper divisors (3436195).

127137809 is an equidigital number, since it uses as much as digits as its factorization.

127137809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3436194.

The product of its (nonzero) digits is 21168, while the sum is 38.

The square root of 127137809 is about 11275.5402974758. The cubic root of 127137809 is about 502.8343149587.

The spelling of 127137809 in words is "one hundred twenty-seven million, one hundred thirty-seven thousand, eight hundred nine".