1200665165521 has 2 divisors, whose sum is σ = 1200665165522. Its totient is φ = 1200665165520.

The previous prime is 1200665165473. The next prime is 1200665165527. The reversal of 1200665165521 is 1255615660021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1198672435921 + 1992729600 = 1094839^2 + 44640^2 .

It is a cyclic number.

It is not a de Polignac number, because 1200665165521 - 2¹¹ = 1200665163473 is a prime.

It is not a weakly prime, because it can be changed into another prime (1200665165527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 600332582760 + 600332582761.

It is an arithmetic number, because the mean of its divisors is an integer number (600332582761).

Almost surely, 2^{1200665165521} is an apocalyptic number.

It is an amenable number.

1200665165521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200665165521 is an equidigital number, since it uses as much as digits as its factorization.

1200665165521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 1200665165521 in words is "one trillion, two hundred billion, six hundred sixty-five million, one hundred sixty-five thousand, five hundred twenty-one".