2001221101987 has 2 divisors, whose sum is σ = 2001221101988. Its totient is φ = 2001221101986.

The previous prime is 2001221101949. The next prime is 2001221101991. The reversal of 2001221101987 is 7891011221002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2001221101987 - 2¹⁵ = 2001221069219 is a prime.

It is not a weakly prime, because it can be changed into another prime (2001221101787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000610550993 + 1000610550994.

It is an arithmetic number, because the mean of its divisors is an integer number (1000610550994).

Almost surely, 2^{2001221101987} is an apocalyptic number.

2001221101987 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001221101987 is an equidigital number, since it uses as much as digits as its factorization.

2001221101987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 34.

Adding to 2001221101987 its reverse (7891011221002), we get a palindrome (9892232322989).

The spelling of 2001221101987 in words is "two trillion, one billion, two hundred twenty-one million, one hundred one thousand, nine hundred eighty-seven".