1191535220261 has 2 divisors, whose sum is σ = 1191535220262. Its totient is φ = 1191535220260.

The previous prime is 1191535220257. The next prime is 1191535220273. The reversal of 1191535220261 is 1620225351911.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1188904556161 + 2630664100 = 1090369^2 + 51290^2 .

It is a cyclic number.

It is not a de Polignac number, because 1191535220261 - 2² = 1191535220257 is a prime.

It is a super-2 number, since 2×1191535220261² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1191535225261) 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, 595767610130 + 595767610131.

It is an arithmetic number, because the mean of its divisors is an integer number (595767610131).

Almost surely, 2^{1191535220261} is an apocalyptic number.

It is an amenable number.

1191535220261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191535220261 is an equidigital number, since it uses as much as digits as its factorization.

1191535220261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 1191535220261 in words is "one trillion, one hundred ninety-one billion, five hundred thirty-five million, two hundred twenty thousand, two hundred sixty-one".