231213551 has 2 divisors, whose sum is σ = 231213552. Its totient is φ = 231213550.

The previous prime is 231213497. The next prime is 231213571. The reversal of 231213551 is 155312132.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231213551 - 2¹⁸ = 230951407 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231213571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115606775 + 115606776.

It is an arithmetic number, because the mean of its divisors is an integer number (115606776).

Almost surely, 2^231213551 is an apocalyptic number.

231213551 is a deficient number, since it is larger than the sum of its proper divisors (1).

231213551 is an equidigital number, since it uses as much as digits as its factorization.

231213551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 900, while the sum is 23.

The square root of 231213551 is about 15205.7078427806. The cubic root of 231213551 is about 613.7682628756.

Adding to 231213551 its reverse (155312132), we get a palindrome (386525683).

The spelling of 231213551 in words is "two hundred thirty-one million, two hundred thirteen thousand, five hundred fifty-one".