1221311057 has 2 divisors, whose sum is σ = 1221311058. Its totient is φ = 1221311056.

The previous prime is 1221310997. The next prime is 1221311071. The reversal of 1221311057 is 7501131221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1118166721 + 103144336 = 33439^2 + 10156^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221311057 - 2¹⁰ = 1221310033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221311857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610655528 + 610655529.

It is an arithmetic number, because the mean of its divisors is an integer number (610655529).

Almost surely, 2^1221311057 is an apocalyptic number.

It is an amenable number.

1221311057 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221311057 is an equidigital number, since it uses as much as digits as its factorization.

1221311057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 420, while the sum is 23.

The square root of 1221311057 is about 34947.2610800904. The cubic root of 1221311057 is about 1068.9123536082.

Adding to 1221311057 its reverse (7501131221), we get a palindrome (8722442278).

The spelling of 1221311057 in words is "one billion, two hundred twenty-one million, three hundred eleven thousand, fifty-seven".