231002221 has 2 divisors, whose sum is σ = 231002222. Its totient is φ = 231002220.

The previous prime is 231002203. The next prime is 231002267. The reversal of 231002221 is 122200132.

231002221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217238121 + 13764100 = 14739^2 + 3710^2 .

It is a cyclic number.

It is not a de Polignac number, because 231002221 - 2⁹ = 231001709 is a prime.

It is a super-2 number, since 2×231002221² = 106724052213865682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231002201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115501110 + 115501111.

It is an arithmetic number, because the mean of its divisors is an integer number (115501111).

Almost surely, 2^231002221 is an apocalyptic number.

It is an amenable number.

231002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

231002221 is an equidigital number, since it uses as much as digits as its factorization.

231002221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 231002221 is about 15198.7572189308. The cubic root of 231002221 is about 613.5812104238.

Adding to 231002221 its reverse (122200132), we get a palindrome (353202353).

The spelling of 231002221 in words is "two hundred thirty-one million, two thousand, two hundred twenty-one".