231208421 has 2 divisors, whose sum is σ = 231208422. Its totient is φ = 231208420.

The previous prime is 231208409. The next prime is 231208427. The reversal of 231208421 is 124802132.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 230128900 + 1079521 = 15170^2 + 1039^2 .

It is a cyclic number.

It is not a de Polignac number, because 231208421 - 2¹⁰ = 231207397 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 (231208427) 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, 115604210 + 115604211.

It is an arithmetic number, because the mean of its divisors is an integer number (115604211).

Almost surely, 2^231208421 is an apocalyptic number.

It is an amenable number.

231208421 is a deficient number, since it is larger than the sum of its proper divisors (1).

231208421 is an equidigital number, since it uses as much as digits as its factorization.

231208421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 231208421 is about 15205.5391551895. The cubic root of 231208421 is about 613.7637235591.

The spelling of 231208421 in words is "two hundred thirty-one million, two hundred eight thousand, four hundred twenty-one".