2001320261 has 2 divisors, whose sum is σ = 2001320262. Its totient is φ = 2001320260.

The previous prime is 2001320231. The next prime is 2001320311. The reversal of 2001320261 is 1620231002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1805740036 + 195580225 = 42494^2 + 13985^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001320261 - 2⁶ = 2001320197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001320231) 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, 1000660130 + 1000660131.

It is an arithmetic number, because the mean of its divisors is an integer number (1000660131).

Almost surely, 2^2001320261 is an apocalyptic number.

It is an amenable number.

2001320261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001320261 is an equidigital number, since it uses as much as digits as its factorization.

2001320261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 2001320261 is about 44736.1180814786. The cubic root of 2001320261 is about 1260.1982263505.

Adding to 2001320261 its reverse (1620231002), we get a palindrome (3621551263).

The spelling of 2001320261 in words is "two billion, one million, three hundred twenty thousand, two hundred sixty-one".