161665783 has 2 divisors, whose sum is σ = 161665784. Its totient is φ = 161665782.

The previous prime is 161665711. The next prime is 161665789. The reversal of 161665783 is 387566161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161665783 - 2⁹ = 161665271 is a prime.

It is a super-3 number, since 3×161665783³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161665789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80832891 + 80832892.

It is an arithmetic number, because the mean of its divisors is an integer number (80832892).

Almost surely, 2^161665783 is an apocalyptic number.

161665783 is a deficient number, since it is larger than the sum of its proper divisors (1).

161665783 is an equidigital number, since it uses as much as digits as its factorization.

161665783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 43.

The square root of 161665783 is about 12714.7859989856. The cubic root of 161665783 is about 544.7610354330.

The spelling of 161665783 in words is "one hundred sixty-one million, six hundred sixty-five thousand, seven hundred eighty-three".