121275809 has 4 divisors (see below), whose sum is σ = 121300116. Its totient is φ = 121251504.

The previous prime is 121275799. The next prime is 121275811. The reversal of 121275809 is 908572121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908572121 = 1621 ⋅560501.

It can be written as a sum of positive squares in 2 ways, for example, as 48344209 + 72931600 = 6953^2 + 8540^2 .

It is a cyclic number.

It is not a de Polignac number, because 121275809 - 2⁴ = 121275793 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121275109) 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 in 3 ways as a sum of consecutive naturals, for example, 1634 + ... + 15659.

It is an arithmetic number, because the mean of its divisors is an integer number (30325029).

Almost surely, 2^121275809 is an apocalyptic number.

It is an amenable number.

121275809 is a deficient number, since it is larger than the sum of its proper divisors (24307).

121275809 is an equidigital number, since it uses as much as digits as its factorization.

121275809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24306.

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 121275809 is about 11012.5296367365. The cubic root of 121275809 is about 494.9842650510.

The spelling of 121275809 in words is "one hundred twenty-one million, two hundred seventy-five thousand, eight hundred nine".