1221663131309 has 2 divisors, whose sum is σ = 1221663131310. Its totient is φ = 1221663131308.

The previous prime is 1221663131303. The next prime is 1221663131323. The reversal of 1221663131309 is 9031313661221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 966971322409 + 254691808900 = 983347^2 + 504670^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221663131309 - 2³² = 1217368164013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221663131303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610831565654 + 610831565655.

It is an arithmetic number, because the mean of its divisors is an integer number (610831565655).

Almost surely, 2^{1221663131309} is an apocalyptic number.

It is an amenable number.

1221663131309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221663131309 is an equidigital number, since it uses as much as digits as its factorization.

1221663131309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 38.

The spelling of 1221663131309 in words is "one trillion, two hundred twenty-one billion, six hundred sixty-three million, one hundred thirty-one thousand, three hundred nine".