165990001 has 4 divisors (see below), whose sum is σ = 166032612. Its totient is φ = 165947392.

The previous prime is 165989987. The next prime is 165990037. The reversal of 165990001 is 100099561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64786401 + 101203600 = 8049^2 + 10060^2 .

It is a cyclic number.

It is not a de Polignac number, because 165990001 - 2¹⁷ = 165858929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165990301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14800 + ... + 23473.

It is an arithmetic number, because the mean of its divisors is an integer number (41508153).

Almost surely, 2^165990001 is an apocalyptic number.

It is an amenable number.

165990001 is a deficient number, since it is larger than the sum of its proper divisors (42611).

165990001 is an equidigital number, since it uses as much as digits as its factorization.

165990001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42610.

The product of its (nonzero) digits is 2430, while the sum is 31.

The square root of 165990001 is about 12883.7106844263. The cubic root of 165990001 is about 549.5754310187.

The spelling of 165990001 in words is "one hundred sixty-five million, nine hundred ninety thousand, one".