121782409 has 4 divisors (see below), whose sum is σ = 139179904. Its totient is φ = 104384916.

The previous prime is 121782391. The next prime is 121782443. The reversal of 121782409 is 904287121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121782409 - 2¹¹ = 121780361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121782449) 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, 8698737 + ... + 8698750.

It is an arithmetic number, because the mean of its divisors is an integer number (34794976).

Almost surely, 2^121782409 is an apocalyptic number.

It is an amenable number.

121782409 is a deficient number, since it is larger than the sum of its proper divisors (17397495).

121782409 is an equidigital number, since it uses as much as digits as its factorization.

121782409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17397494.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 121782409 is about 11035.5067396110. The cubic root of 121782409 is about 495.6725327753.

The spelling of 121782409 in words is "one hundred twenty-one million, seven hundred eighty-two thousand, four hundred nine".