1221211515061 has 2 divisors, whose sum is σ = 1221211515062. Its totient is φ = 1221211515060.

The previous prime is 1221211515059. The next prime is 1221211515091. The reversal of 1221211515061 is 1605151121221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 866584119025 + 354627396036 = 930905^2 + 595506^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221211515061 - 2¹ = 1221211515059 is a prime.

Together with 1221211515059, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221211515091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610605757530 + 610605757531.

It is an arithmetic number, because the mean of its divisors is an integer number (610605757531).

Almost surely, 2^{1221211515061} is an apocalyptic number.

It is an amenable number.

1221211515061 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221211515061 is an equidigital number, since it uses as much as digits as its factorization.

1221211515061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 28.

Adding to 1221211515061 its reverse (1605151121221), we get a palindrome (2826362636282).

The spelling of 1221211515061 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, five hundred fifteen thousand, sixty-one".