231321220187 has 2 divisors, whose sum is σ = 231321220188. Its totient is φ = 231321220186.

The previous prime is 231321220181. The next prime is 231321220189. The reversal of 231321220187 is 781022123132.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231321220187 - 2²⁸ = 231052784731 is a prime.

Together with 231321220189, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231321220181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115660610093 + 115660610094.

It is an arithmetic number, because the mean of its divisors is an integer number (115660610094).

Almost surely, 2^231321220187 is an apocalyptic number.

231321220187 is a deficient number, since it is larger than the sum of its proper divisors (1).

231321220187 is an equidigital number, since it uses as much as digits as its factorization.

231321220187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 32.

The spelling of 231321220187 in words is "two hundred thirty-one billion, three hundred twenty-one million, two hundred twenty thousand, one hundred eighty-seven".