231187993 has 2 divisors, whose sum is σ = 231187994. Its totient is φ = 231187992.

The previous prime is 231187933. The next prime is 231188003. The reversal of 231187993 is 399781132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215884249 + 15303744 = 14693^2 + 3912^2 .

It is a cyclic number.

It is not a de Polignac number, because 231187993 - 2¹³ = 231179801 is a prime.

It is not a weakly prime, because it can be changed into another prime (231187903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115593996 + 115593997.

It is an arithmetic number, because the mean of its divisors is an integer number (115593997).

Almost surely, 2^231187993 is an apocalyptic number.

It is an amenable number.

231187993 is a deficient number, since it is larger than the sum of its proper divisors (1).

231187993 is an equidigital number, since it uses as much as digits as its factorization.

231187993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 43.

The square root of 231187993 is about 15204.8674114574. The cubic root of 231187993 is about 613.7456470338.

The spelling of 231187993 in words is "two hundred thirty-one million, one hundred eighty-seven thousand, nine hundred ninety-three".