121809605 has 4 divisors (see below), whose sum is σ = 146171532. Its totient is φ = 97447680.

The previous prime is 121809581. The next prime is 121809613. The reversal of 121809605 is 506908121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 52287361 + 69522244 = 7231^2 + 8338^2 .

It is not a de Polignac number, because 121809605 - 2²⁶ = 54700741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 12180956 + ... + 12180965.

It is an arithmetic number, because the mean of its divisors is an integer number (36542883).

Almost surely, 2^121809605 is an apocalyptic number.

It is an amenable number.

121809605 is a deficient number, since it is larger than the sum of its proper divisors (24361927).

121809605 is an equidigital number, since it uses as much as digits as its factorization.

121809605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24361926.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 121809605 is about 11036.7388752294. The cubic root of 121809605 is about 495.7094272852.

The spelling of 121809605 in words is "one hundred twenty-one million, eight hundred nine thousand, six hundred five".