2001312991 has 2 divisors, whose sum is σ = 2001312992. Its totient is φ = 2001312990.

The previous prime is 2001312983. The next prime is 2001313051. The reversal of 2001312991 is 1992131002.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2001312991 - 2³ = 2001312983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001312091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000656495 + 1000656496.

It is an arithmetic number, because the mean of its divisors is an integer number (1000656496).

Almost surely, 2^2001312991 is an apocalyptic number.

2001312991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001312991 is an equidigital number, since it uses as much as digits as its factorization.

2001312991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 2001312991 is about 44736.0368271486. The cubic root of 2001312991 is about 1260.1967004158.

Adding to 2001312991 its reverse (1992131002), we get a palindrome (3993443993).

The spelling of 2001312991 in words is "two billion, one million, three hundred twelve thousand, nine hundred ninety-one".