165278881 has 2 divisors, whose sum is σ = 165278882. Its totient is φ = 165278880.

The previous prime is 165278849. The next prime is 165278957. The reversal of 165278881 is 188872561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 153140625 + 12138256 = 12375^2 + 3484^2 .

It is an emirp because it is prime and its reverse (188872561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165278881 - 2⁵ = 165278849 is a prime.

It is a super-2 number, since 2×165278881² = 54634217009224322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (165278381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82639440 + 82639441.

It is an arithmetic number, because the mean of its divisors is an integer number (82639441).

Almost surely, 2^165278881 is an apocalyptic number.

It is an amenable number.

165278881 is a deficient number, since it is larger than the sum of its proper divisors (1).

165278881 is an equidigital number, since it uses as much as digits as its factorization.

165278881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 215040, while the sum is 46.

The square root of 165278881 is about 12856.0834238115. The cubic root of 165278881 is about 548.7894930956.

The spelling of 165278881 in words is "one hundred sixty-five million, two hundred seventy-eight thousand, eight hundred eighty-one".