1331231210261 has 2 divisors, whose sum is σ = 1331231210262. Its totient is φ = 1331231210260.

The previous prime is 1331231210227. The next prime is 1331231210273. The reversal of 1331231210261 is 1620121321331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1115387342161 + 215843868100 = 1056119^2 + 464590^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331231210261 - 2²² = 1331227015957 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1331231210261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331231210201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665615605130 + 665615605131.

It is an arithmetic number, because the mean of its divisors is an integer number (665615605131).

Almost surely, 2^{1331231210261} is an apocalyptic number.

It is an amenable number.

1331231210261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331231210261 is an equidigital number, since it uses as much as digits as its factorization.

1331231210261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

Adding to 1331231210261 its reverse (1620121321331), we get a palindrome (2951352531592).

The spelling of 1331231210261 in words is "one trillion, three hundred thirty-one billion, two hundred thirty-one million, two hundred ten thousand, two hundred sixty-one".