231220121 has 4 divisors (see below), whose sum is σ = 252240144. Its totient is φ = 210200100.

The previous prime is 231220097. The next prime is 231220153. The reversal of 231220121 is 121022132.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 231220121 - 2⁶ = 231220057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231220096 and 231220105.

It is not an unprimeable number, because it can be changed into a prime (231220021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10509995 + ... + 10510016.

It is an arithmetic number, because the mean of its divisors is an integer number (63060036).

Almost surely, 2^231220121 is an apocalyptic number.

It is an amenable number.

231220121 is a deficient number, since it is larger than the sum of its proper divisors (21020023).

231220121 is a wasteful number, since it uses less digits than its factorization.

231220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21020022.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 231220121 is about 15205.9238785415. The cubic root of 231220121 is about 613.7740762882.

Adding to 231220121 its reverse (121022132), we get a palindrome (352242253).

The spelling of 231220121 in words is "two hundred thirty-one million, two hundred twenty thousand, one hundred twenty-one".