2001121987 has 2 divisors, whose sum is σ = 2001121988. Its totient is φ = 2001121986.

The previous prime is 2001121981. The next prime is 2001121999. The reversal of 2001121987 is 7891211002.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001121987 is a prime.

It is not a weakly prime, because it can be changed into another prime (2001121981) 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, 1000560993 + 1000560994.

It is an arithmetic number, because the mean of its divisors is an integer number (1000560994).

Almost surely, 2^2001121987 is an apocalyptic number.

2001121987 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001121987 is an equidigital number, since it uses as much as digits as its factorization.

2001121987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 31.

The square root of 2001121987 is about 44733.9019871953. The cubic root of 2001121987 is about 1260.1566083579.

Adding to 2001121987 its reverse (7891211002), we get a palindrome (9892332989).

The spelling of 2001121987 in words is "two billion, one million, one hundred twenty-one thousand, nine hundred eighty-seven".