231721151 has 2 divisors, whose sum is σ = 231721152. Its totient is φ = 231721150.

The previous prime is 231721117. The next prime is 231721157. The reversal of 231721151 is 151127132.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231721151 - 2¹⁰ = 231720127 is a 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 (231721157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115860575 + 115860576.

It is an arithmetic number, because the mean of its divisors is an integer number (115860576).

Almost surely, 2^231721151 is an apocalyptic number.

231721151 is a deficient number, since it is larger than the sum of its proper divisors (1).

231721151 is an equidigital number, since it uses as much as digits as its factorization.

231721151 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 23.

The square root of 231721151 is about 15222.3897926705. The cubic root of 231721151 is about 614.2170846942.

Adding to 231721151 its reverse (151127132), we get a palindrome (382848283).

The spelling of 231721151 in words is "two hundred thirty-one million, seven hundred twenty-one thousand, one hundred fifty-one".