231221951 has 2 divisors, whose sum is σ = 231221952. Its totient is φ = 231221950.

The previous prime is 231221941. The next prime is 231221957. The reversal of 231221951 is 159122132.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231221951 - 2¹⁴ = 231205567 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 231221951.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231221957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115610975 + 115610976.

It is an arithmetic number, because the mean of its divisors is an integer number (115610976).

Almost surely, 2^231221951 is an apocalyptic number.

231221951 is a deficient number, since it is larger than the sum of its proper divisors (1).

231221951 is an equidigital number, since it uses as much as digits as its factorization.

231221951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 26.

The square root of 231221951 is about 15205.9840523394. The cubic root of 231221951 is about 613.7756955296.

The spelling of 231221951 in words is "two hundred thirty-one million, two hundred twenty-one thousand, nine hundred fifty-one".