165678109 has 2 divisors, whose sum is σ = 165678110. Its totient is φ = 165678108.

The previous prime is 165678091. The next prime is 165678127. The reversal of 165678109 is 901876561.

It is a happy number.

Together with previous prime (165678091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (165678091) and next prime (165678127).

It can be written as a sum of positive squares in only one way, i.e., 165636900 + 41209 = 12870^2 + 203^2 .

It is a cyclic number.

It is not a de Polignac number, because 165678109 - 2²¹ = 163580957 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165678179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82839054 + 82839055.

It is an arithmetic number, because the mean of its divisors is an integer number (82839055).

Almost surely, 2^165678109 is an apocalyptic number.

It is an amenable number.

165678109 is a deficient number, since it is larger than the sum of its proper divisors (1).

165678109 is an equidigital number, since it uses as much as digits as its factorization.

165678109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 165678109 is about 12871.6008716865. The cubic root of 165678109 is about 549.2310013361.

The spelling of 165678109 in words is "one hundred sixty-five million, six hundred seventy-eight thousand, one hundred nine".