321220121987 has 2 divisors, whose sum is σ = 321220121988. Its totient is φ = 321220121986.

The previous prime is 321220121921. The next prime is 321220122019. The reversal of 321220121987 is 789121022123.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 321220121987 - 2⁸ = 321220121731 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 321220121987.

It is not a weakly prime, because it can be changed into another prime (321220111987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160610060993 + 160610060994.

It is an arithmetic number, because the mean of its divisors is an integer number (160610060994).

Almost surely, 2^321220121987 is an apocalyptic number.

321220121987 is a deficient number, since it is larger than the sum of its proper divisors (1).

321220121987 is an equidigital number, since it uses as much as digits as its factorization.

321220121987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 321220121987 in words is "three hundred twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, nine hundred eighty-seven".