121979809 has 8 divisors (see below), whose sum is σ = 141691328. Its totient is φ = 102839760.

The previous prime is 121979807. The next prime is 121979831. The reversal of 121979809 is 908979121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121979809 - 2¹ = 121979807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121979807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142407 + ... + 143260.

It is an arithmetic number, because the mean of its divisors is an integer number (17711416).

Almost surely, 2^121979809 is an apocalyptic number.

It is an amenable number.

121979809 is a deficient number, since it is larger than the sum of its proper divisors (19711519).

121979809 is an equidigital number, since it uses as much as digits as its factorization.

121979809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285735.

The product of its (nonzero) digits is 81648, while the sum is 46.

The square root of 121979809 is about 11044.4469757431. The cubic root of 121979809 is about 495.9402039973.

The spelling of 121979809 in words is "one hundred twenty-one million, nine hundred seventy-nine thousand, eight hundred nine".