166521223 has 4 divisors (see below), whose sum is σ = 181659528. Its totient is φ = 151382920.

The previous prime is 166521221. The next prime is 166521247. The reversal of 166521223 is 322125661.

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

It is a cyclic number.

It is not a de Polignac number, because 166521223 - 2¹ = 166521221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 166521191 and 166521200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166521221) 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, 7569136 + ... + 7569157.

It is an arithmetic number, because the mean of its divisors is an integer number (45414882).

Almost surely, 2^166521223 is an apocalyptic number.

166521223 is a deficient number, since it is larger than the sum of its proper divisors (15138305).

166521223 is a wasteful number, since it uses less digits than its factorization.

166521223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15138304.

The product of its digits is 4320, while the sum is 28.

The square root of 166521223 is about 12904.3102489052. The cubic root of 166521223 is about 550.1610800921.

Adding to 166521223 its reverse (322125661), we get a palindrome (488646884).

The spelling of 166521223 in words is "one hundred sixty-six million, five hundred twenty-one thousand, two hundred twenty-three".