311213561 has 2 divisors, whose sum is σ = 311213562. Its totient is φ = 311213560.

The previous prime is 311213537. The next prime is 311213579. The reversal of 311213561 is 165312113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 261016336 + 50197225 = 16156^2 + 7085^2 .

It is a cyclic number.

It is not a de Polignac number, because 311213561 - 2¹⁰ = 311212537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (311218561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155606780 + 155606781.

It is an arithmetic number, because the mean of its divisors is an integer number (155606781).

Almost surely, 2^311213561 is an apocalyptic number.

It is an amenable number.

311213561 is a deficient number, since it is larger than the sum of its proper divisors (1).

311213561 is an equidigital number, since it uses as much as digits as its factorization.

311213561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 23.

The square root of 311213561 is about 17641.2460160840. The cubic root of 311213561 is about 677.6719413998.

Adding to 311213561 its reverse (165312113), we get a palindrome (476525674).

The spelling of 311213561 in words is "three hundred eleven million, two hundred thirteen thousand, five hundred sixty-one".