231131987 has 2 divisors, whose sum is σ = 231131988. Its totient is φ = 231131986.

The previous prime is 231131951. The next prime is 231132019. The reversal of 231131987 is 789131132.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231131987 - 2¹² = 231127891 is a prime.

It is not a weakly prime, because it can be changed into another prime (231131917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115565993 + 115565994.

It is an arithmetic number, because the mean of its divisors is an integer number (115565994).

Almost surely, 2^231131987 is an apocalyptic number.

231131987 is a deficient number, since it is larger than the sum of its proper divisors (1).

231131987 is an equidigital number, since it uses as much as digits as its factorization.

231131987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 231131987 is about 15203.0255870337. The cubic root of 231131987 is about 613.6960824431.

The spelling of 231131987 in words is "two hundred thirty-one million, one hundred thirty-one thousand, nine hundred eighty-seven".