231721253 has 2 divisors, whose sum is σ = 231721254. Its totient is φ = 231721252.

The previous prime is 231721241. The next prime is 231721277. The reversal of 231721253 is 352127132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 210772324 + 20948929 = 14518^2 + 4577^2 .

It is a cyclic number.

It is not a de Polignac number, because 231721253 - 2²⁶ = 164612389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231721213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115860626 + 115860627.

It is an arithmetic number, because the mean of its divisors is an integer number (115860627).

Almost surely, 2^231721253 is an apocalyptic number.

It is an amenable number.

231721253 is a deficient number, since it is larger than the sum of its proper divisors (1).

231721253 is an equidigital number, since it uses as much as digits as its factorization.

231721253 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 26.

The square root of 231721253 is about 15222.3931429982. The cubic root of 231721253 is about 614.2171748171.

Adding to 231721253 its reverse (352127132), we get a palindrome (583848385).

The spelling of 231721253 in words is "two hundred thirty-one million, seven hundred twenty-one thousand, two hundred fifty-three".