165986401 has 16 divisors (see below), whose sum is σ = 197049600. Its totient is φ = 136801728.

The previous prime is 165986371. The next prime is 165986437. The reversal of 165986401 is 104689561.

It is not a de Polignac number, because 165986401 - 2⁷ = 165986273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165986441) 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 in 15 ways as a sum of consecutive naturals, for example, 51835 + ... + 54943.

It is an arithmetic number, because the mean of its divisors is an integer number (12315600).

Almost surely, 2^165986401 is an apocalyptic number.

It is an amenable number.

165986401 is a deficient number, since it is larger than the sum of its proper divisors (31063199).

165986401 is a wasteful number, since it uses less digits than its factorization.

165986401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3408.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 165986401 is about 12883.5709723663. The cubic root of 165986401 is about 549.5714579162.

The spelling of 165986401 in words is "one hundred sixty-five million, nine hundred eighty-six thousand, four hundred one".