231551 has 2 divisors, whose sum is σ = 231552. Its totient is φ = 231550.

The previous prime is 231547. The next prime is 231559. The reversal of 231551 is 155132.

231551 is nontrivially palindromic in base 13.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231551 - 2² = 231547 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115775 + 115776.

It is an arithmetic number, because the mean of its divisors is an integer number (115776).

2²³¹⁵⁵¹ is an apocalyptic number.

231551 is a deficient number, since it is larger than the sum of its proper divisors (1).

231551 is an equidigital number, since it uses as much as digits as its factorization.

231551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150, while the sum is 17.

The square root of 231551 is about 481.1974646650. The cubic root of 231551 is about 61.4066709640.

Adding to 231551 its reverse (155132), we get a palindrome (386683).

The spelling of 231551 in words is "two hundred thirty-one thousand, five hundred fifty-one".