1221021199987 has 2 divisors, whose sum is σ = 1221021199988. Its totient is φ = 1221021199986.

The previous prime is 1221021199969. The next prime is 1221021199999. The reversal of 1221021199987 is 7899911201221.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221021199987 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221021191987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510599993 + 610510599994.

It is an arithmetic number, because the mean of its divisors is an integer number (610510599994).

Almost surely, 2^{1221021199987} is an apocalyptic number.

1221021199987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221021199987 is an equidigital number, since it uses as much as digits as its factorization.

1221021199987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 52.

The spelling of 1221021199987 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one hundred ninety-nine thousand, nine hundred eighty-seven".