231211961 has 2 divisors, whose sum is σ = 231211962. Its totient is φ = 231211960.

The previous prime is 231211957. The next prime is 231212057. The reversal of 231211961 is 169112132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 142945936 + 88266025 = 11956^2 + 9395^2 .

It is a cyclic number.

It is not a de Polignac number, because 231211961 - 2² = 231211957 is a 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 231211961.

It is not a weakly prime, because it can be changed into another prime (231211921) 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, 115605980 + 115605981.

It is an arithmetic number, because the mean of its divisors is an integer number (115605981).

Almost surely, 2^231211961 is an apocalyptic number.

It is an amenable number.

231211961 is a deficient number, since it is larger than the sum of its proper divisors (1).

231211961 is an equidigital number, since it uses as much as digits as its factorization.

231211961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 26.

The square root of 231211961 is about 15205.6555596923. The cubic root of 231211961 is about 613.7668559601.

The spelling of 231211961 in words is "two hundred thirty-one million, two hundred eleven thousand, nine hundred sixty-one".