165550001 has 2 divisors, whose sum is σ = 165550002. Its totient is φ = 165550000.

The previous prime is 165549991. The next prime is 165550003. The reversal of 165550001 is 100055561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160149025 + 5400976 = 12655^2 + 2324^2 .

It is an emirp because it is prime and its reverse (100055561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165550001 - 2²⁶ = 98441137 is a prime.

It is a super-2 number, since 2×165550001² = 54813605662200002, which contains 22 as substring.

Together with 165550003, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165550003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82775000 + 82775001.

It is an arithmetic number, because the mean of its divisors is an integer number (82775001).

Almost surely, 2^165550001 is an apocalyptic number.

It is an amenable number.

165550001 is a deficient number, since it is larger than the sum of its proper divisors (1).

165550001 is an equidigital number, since it uses as much as digits as its factorization.

165550001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 165550001 is about 12866.6235275615. The cubic root of 165550001 is about 549.0894034137.

The spelling of 165550001 in words is "one hundred sixty-five million, five hundred fifty thousand, one".