166556393 has 4 divisors (see below), whose sum is σ = 167428608. Its totient is φ = 165684180.

The previous prime is 166556389. The next prime is 166556399. The reversal of 166556393 is 393655661.

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.

It is a cyclic number.

It is not a de Polignac number, because 166556393 - 2² = 166556389 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166556399) 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, 435821 + ... + 436202.

It is an arithmetic number, because the mean of its divisors is an integer number (41857152).

Almost surely, 2^166556393 is an apocalyptic number.

It is an amenable number.

166556393 is a deficient number, since it is larger than the sum of its proper divisors (872215).

166556393 is an equidigital number, since it uses as much as digits as its factorization.

166556393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 872214.

The product of its digits is 437400, while the sum is 44.

The square root of 166556393 is about 12905.6728999305. The cubic root of 166556393 is about 550.1998094961.

The spelling of 166556393 in words is "one hundred sixty-six million, five hundred fifty-six thousand, three hundred ninety-three".