231238921 has 2 divisors, whose sum is σ = 231238922. Its totient is φ = 231238920.

The previous prime is 231238901. The next prime is 231238927. The reversal of 231238921 is 129832132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 162945225 + 68293696 = 12765^2 + 8264^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231238921 is a prime.

It is not a weakly prime, because it can be changed into another prime (231238927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115619460 + 115619461.

It is an arithmetic number, because the mean of its divisors is an integer number (115619461).

Almost surely, 2^231238921 is an apocalyptic number.

It is an amenable number.

231238921 is a deficient number, since it is larger than the sum of its proper divisors (1).

231238921 is an equidigital number, since it uses as much as digits as its factorization.

231238921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 231238921 is about 15206.5420461063. The cubic root of 231238921 is about 613.7907107112.

The spelling of 231238921 in words is "two hundred thirty-one million, two hundred thirty-eight thousand, nine hundred twenty-one".