121221865 has 16 divisors (see below), whose sum is σ = 148651200. Its totient is φ = 94865472.

The previous prime is 121221857. The next prime is 121221869. The reversal of 121221865 is 568122121.

It is a cyclic number.

It is not a de Polignac number, because 121221865 - 2³ = 121221857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121221869) 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, 163666 + ... + 164404.

It is an arithmetic number, because the mean of its divisors is an integer number (9290700).

Almost surely, 2^121221865 is an apocalyptic number.

It is an amenable number.

121221865 is a deficient number, since it is larger than the sum of its proper divisors (27429335).

121221865 is an equidigital number, since it uses as much as digits as its factorization.

121221865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1416.

The product of its digits is 1920, while the sum is 28.

The square root of 121221865 is about 11010.0801541133. The cubic root of 121221865 is about 494.9108637921.

Adding to 121221865 its reverse (568122121), we get a palindrome (689343986).

The spelling of 121221865 in words is "one hundred twenty-one million, two hundred twenty-one thousand, eight hundred sixty-five".