231311212121221 has 32 divisors (see below), whose sum is σ = 243320760004608. Its totient is φ = 219703635264960.

The previous prime is 231311212121201. The next prime is 231311212121233. The reversal of 231311212121221 is 122121212113132.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 231311212121221 - 2²⁵ = 231311178566789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231311212121201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92838036 + ... + 95297026.

It is an arithmetic number, because the mean of its divisors is an integer number (7603773750144).

Almost surely, 2^{231311212121221} is an apocalyptic number.

It is an amenable number.

231311212121221 is a deficient number, since it is larger than the sum of its proper divisors (12009547883387).

231311212121221 is a wasteful number, since it uses less digits than its factorization.

231311212121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2459521.

The product of its digits is 576, while the sum is 25.

Adding to 231311212121221 its reverse (122121212113132), we get a palindrome (353432424234353).

The spelling of 231311212121221 in words is "two hundred thirty-one trillion, three hundred eleven billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".