165933993 has 4 divisors (see below), whose sum is σ = 221245328. Its totient is φ = 110622660.

The previous prime is 165933959. The next prime is 165934001. The reversal of 165933993 is 399339561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 399339561 = 3 ⋅133113187.

It is not a de Polignac number, because 165933993 - 2²² = 161739689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165933913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27655663 + ... + 27655668.

It is an arithmetic number, because the mean of its divisors is an integer number (55311332).

Almost surely, 2^165933993 is an apocalyptic number.

It is an amenable number.

165933993 is a deficient number, since it is larger than the sum of its proper divisors (55311335).

165933993 is an equidigital number, since it uses as much as digits as its factorization.

165933993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55311334.

The product of its digits is 590490, while the sum is 48.

The square root of 165933993 is about 12881.5369036462. The cubic root of 165933993 is about 549.5136118666.

The spelling of 165933993 in words is "one hundred sixty-five million, nine hundred thirty-three thousand, nine hundred ninety-three".