165554993 has 4 divisors (see below), whose sum is σ = 175293540. Its totient is φ = 155816448.

The previous prime is 165554981. The next prime is 165555011. The reversal of 165554993 is 399455561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 399455561 = 7451 ⋅53611.

It can be written as a sum of positive squares in 2 ways, for example, as 73068304 + 92486689 = 8548^2 + 9617^2 .

It is a cyclic number.

It is not a de Polignac number, because 165554993 - 2⁸ = 165554737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165554933) 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, 4869248 + ... + 4869281.

It is an arithmetic number, because the mean of its divisors is an integer number (43823385).

Almost surely, 2^165554993 is an apocalyptic number.

It is an amenable number.

165554993 is a deficient number, since it is larger than the sum of its proper divisors (9738547).

165554993 is an equidigital number, since it uses as much as digits as its factorization.

165554993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9738546.

The product of its digits is 729000, while the sum is 47.

The square root of 165554993 is about 12866.8175163869. The cubic root of 165554993 is about 549.0949224447.

The spelling of 165554993 in words is "one hundred sixty-five million, five hundred fifty-four thousand, nine hundred ninety-three".