231565421 has 2 divisors, whose sum is σ = 231565422. Its totient is φ = 231565420.

The previous prime is 231565409. The next prime is 231565429. The reversal of 231565421 is 124565132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 221712100 + 9853321 = 14890^2 + 3139^2 .

It is a cyclic number.

It is not a de Polignac number, because 231565421 - 2²⁶ = 164456557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231565429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115782710 + 115782711.

It is an arithmetic number, because the mean of its divisors is an integer number (115782711).

Almost surely, 2^231565421 is an apocalyptic number.

It is an amenable number.

231565421 is a deficient number, since it is larger than the sum of its proper divisors (1).

231565421 is an equidigital number, since it uses as much as digits as its factorization.

231565421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 29.

The square root of 231565421 is about 15217.2737702914. The cubic root of 231565421 is about 614.0794574037.

The spelling of 231565421 in words is "two hundred thirty-one million, five hundred sixty-five thousand, four hundred twenty-one".