165511234661 has 2 divisors, whose sum is σ = 165511234662. Its totient is φ = 165511234660.

The previous prime is 165511234649. The next prime is 165511234727. The reversal of 165511234661 is 166432115561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136534684036 + 28976550625 = 369506^2 + 170225^2 .

It is an emirp because it is prime and its reverse (166432115561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165511234661 - 2¹⁴ = 165511218277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165511234961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82755617330 + 82755617331.

It is an arithmetic number, because the mean of its divisors is an integer number (82755617331).

Almost surely, 2^165511234661 is an apocalyptic number.

It is an amenable number.

165511234661 is a deficient number, since it is larger than the sum of its proper divisors (1).

165511234661 is an equidigital number, since it uses as much as digits as its factorization.

165511234661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 41.

The spelling of 165511234661 in words is "one hundred sixty-five billion, five hundred eleven million, two hundred thirty-four thousand, six hundred sixty-one".