231481155991 has 2 divisors, whose sum is σ = 231481155992. Its totient is φ = 231481155990.

The previous prime is 231481155977. The next prime is 231481156007. The reversal of 231481155991 is 199551184132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231481155991 - 2¹⁷ = 231481024919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231481155691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115740577995 + 115740577996.

It is an arithmetic number, because the mean of its divisors is an integer number (115740577996).

Almost surely, 2^231481155991 is an apocalyptic number.

231481155991 is a deficient number, since it is larger than the sum of its proper divisors (1).

231481155991 is an equidigital number, since it uses as much as digits as its factorization.

231481155991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 388800, while the sum is 49.

The spelling of 231481155991 in words is "two hundred thirty-one billion, four hundred eighty-one million, one hundred fifty-five thousand, nine hundred ninety-one".