1221321029987 has 2 divisors, whose sum is σ = 1221321029988. Its totient is φ = 1221321029986.

The previous prime is 1221321029983. The next prime is 1221321030049. The reversal of 1221321029987 is 7899201231221.

It is a weak prime.

It is an emirp because it is prime and its reverse (7899201231221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221321029987 - 2² = 1221321029983 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221321029983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610660514993 + 610660514994.

It is an arithmetic number, because the mean of its divisors is an integer number (610660514994).

Almost surely, 2^{1221321029987} is an apocalyptic number.

1221321029987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221321029987 is an equidigital number, since it uses as much as digits as its factorization.

1221321029987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 217728, while the sum is 47.

The spelling of 1221321029987 in words is "one trillion, two hundred twenty-one billion, three hundred twenty-one million, twenty-nine thousand, nine hundred eighty-seven".