20221221199987 has 2 divisors, whose sum is σ = 20221221199988. Its totient is φ = 20221221199986.

The previous prime is 20221221199973. The next prime is 20221221199999. The reversal of 20221221199987 is 78999112212202.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20221221199987 - 2⁷ = 20221221199859 is a prime.

It is not a weakly prime, because it can be changed into another prime (20221221199957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10110610599993 + 10110610599994.

It is an arithmetic number, because the mean of its divisors is an integer number (10110610599994).

Almost surely, 2^{20221221199987} is an apocalyptic number.

20221221199987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20221221199987 is an equidigital number, since it uses as much as digits as its factorization.

20221221199987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 55.

The spelling of 20221221199987 in words is "twenty trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred ninety-nine thousand, nine hundred eighty-seven".