121185905 has 4 divisors (see below), whose sum is σ = 145423092. Its totient is φ = 96948720.

The previous prime is 121185901. The next prime is 121185907. The reversal of 121185905 is 509581121.

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 16982641 + 104203264 = 4121^2 + 10208^2 .

It is not a de Polignac number, because 121185905 - 2² = 121185901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121185901) 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, 12118586 + ... + 12118595.

It is an arithmetic number, because the mean of its divisors is an integer number (36355773).

Almost surely, 2^121185905 is an apocalyptic number.

It is an amenable number.

121185905 is a deficient number, since it is larger than the sum of its proper divisors (24237187).

121185905 is an equidigital number, since it uses as much as digits as its factorization.

121185905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24237186.

The product of its (nonzero) digits is 3600, while the sum is 32.

The square root of 121185905 is about 11008.4469840210. The cubic root of 121185905 is about 494.8619211509.

The spelling of 121185905 in words is "one hundred twenty-one million, one hundred eighty-five thousand, nine hundred five".