121242509 has 4 divisors (see below), whose sum is σ = 121287804. Its totient is φ = 121197216.

The previous prime is 121242503. The next prime is 121242523. The reversal of 121242509 is 905242121.

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 110040100 + 11202409 = 10490^2 + 3347^2 .

It is a cyclic number.

It is not a de Polignac number, because 121242509 - 2²⁰ = 120193933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121242503) 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, 18362 + ... + 24075.

It is an arithmetic number, because the mean of its divisors is an integer number (30321951).

Almost surely, 2^121242509 is an apocalyptic number.

It is an amenable number.

121242509 is a deficient number, since it is larger than the sum of its proper divisors (45295).

121242509 is an equidigital number, since it uses as much as digits as its factorization.

121242509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45294.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 121242509 is about 11011.0176187308. The cubic root of 121242509 is about 494.9389565237.

The spelling of 121242509 in words is "one hundred twenty-one million, two hundred forty-two thousand, five hundred nine".