121965409 has 4 divisors (see below), whose sum is σ = 122646960. Its totient is φ = 121283860.

The previous prime is 121965391. The next prime is 121965421. The reversal of 121965409 is 904569121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 904569121 = 4211 ⋅214811.

It is a cyclic number.

It is not a de Polignac number, because 121965409 - 2⁷ = 121965281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121965499) 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, 340507 + ... + 340864.

It is an arithmetic number, because the mean of its divisors is an integer number (30661740).

Almost surely, 2^121965409 is an apocalyptic number.

It is an amenable number.

121965409 is a deficient number, since it is larger than the sum of its proper divisors (681551).

121965409 is an equidigital number, since it uses as much as digits as its factorization.

121965409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681550.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 121965409 is about 11043.7950451826. The cubic root of 121965409 is about 495.9206875980.

The spelling of 121965409 in words is "one hundred twenty-one million, nine hundred sixty-five thousand, four hundred nine".