121938809 has 4 divisors (see below), whose sum is σ = 122013540. Its totient is φ = 121864080.

The previous prime is 121938787. The next prime is 121938871. The reversal of 121938809 is 908839121.

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 27071209 + 94867600 = 5203^2 + 9740^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121938809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121934809) 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, 34862 + ... + 38199.

It is an arithmetic number, because the mean of its divisors is an integer number (30503385).

Almost surely, 2^121938809 is an apocalyptic number.

It is an amenable number.

121938809 is a deficient number, since it is larger than the sum of its proper divisors (74731).

121938809 is an equidigital number, since it uses as much as digits as its factorization.

121938809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74730.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 121938809 is about 11042.5906833496. The cubic root of 121938809 is about 495.8846324314.

The spelling of 121938809 in words is "one hundred twenty-one million, nine hundred thirty-eight thousand, eight hundred nine".