121509 has 12 divisors (see below), whose sum is σ = 183456. Its totient is φ = 77352.

The previous prime is 121507. The next prime is 121523. The reversal of 121509 is 905121.

It is not a de Polignac number, because 121509 - 2¹ = 121507 is a prime.

121509 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 121491 and 121500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 87 + ... + 500.

It is an arithmetic number, because the mean of its divisors is an integer number (15288).

2¹²¹⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

121509 is a deficient number, since it is larger than the sum of its proper divisors (61947).

121509 is a wasteful number, since it uses less digits than its factorization.

121509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 121509 is about 348.5814108641. The cubic root of 121509 is about 49.5301316392.

It can be divided in two parts, 121 and 509, that added together give a triangular number (630 = T₃₅).

The spelling of 121509 in words is "one hundred twenty-one thousand, five hundred nine".