121640205 has 16 divisors (see below), whose sum is σ = 194794560. Its totient is φ = 64818048.

The previous prime is 121640159. The next prime is 121640209. The reversal of 121640205 is 502046121.

It is not a de Polignac number, because 121640205 - 2¹⁰ = 121639181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121640209) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18666 + ... + 24324.

It is an arithmetic number, because the mean of its divisors is an integer number (12174660).

Almost surely, 2^121640205 is an apocalyptic number.

121640205 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121640205 is a deficient number, since it is larger than the sum of its proper divisors (73154355).

121640205 is a wasteful number, since it uses less digits than its factorization.

121640205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7100.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 121640205 is about 11029.0618368019. The cubic root of 121640205 is about 495.4795271496.

Adding to 121640205 its reverse (502046121), we get a palindrome (623686326).

The spelling of 121640205 in words is "one hundred twenty-one million, six hundred forty thousand, two hundred five".