121871909 has 4 divisors (see below), whose sum is σ = 128286240. Its totient is φ = 115457580.

The previous prime is 121871903. The next prime is 121871927. The reversal of 121871909 is 909178121.

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 121871909 - 2²⁰ = 120823333 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 (121871903) 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, 3207137 + ... + 3207174.

It is an arithmetic number, because the mean of its divisors is an integer number (32071560).

Almost surely, 2^121871909 is an apocalyptic number.

121871909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

121871909 is a deficient number, since it is larger than the sum of its proper divisors (6414331).

121871909 is an equidigital number, since it uses as much as digits as its factorization.

121871909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6414330.

The product of its (nonzero) digits is 9072, while the sum is 38.

The square root of 121871909 is about 11039.5610872897. The cubic root of 121871909 is about 495.7939291490.

The spelling of 121871909 in words is "one hundred twenty-one million, eight hundred seventy-one thousand, nine hundred nine".