166503021 has 16 divisors (see below), whose sum is σ = 225301824. Its totient is φ = 109364864.

The previous prime is 166503017. The next prime is 166503031. The reversal of 166503021 is 120305661.

It is a cyclic number.

It is not a de Polignac number, because 166503021 - 2² = 166503017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166502982 and 166503000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166503011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61921 + ... + 64553.

It is an arithmetic number, because the mean of its divisors is an integer number (14081364).

Almost surely, 2^166503021 is an apocalyptic number.

It is an amenable number.

166503021 is a deficient number, since it is larger than the sum of its proper divisors (58798803).

166503021 is a wasteful number, since it uses less digits than its factorization.

166503021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2940.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 166503021 is about 12903.6049614052. The cubic root of 166503021 is about 550.1410338048.

Adding to 166503021 its reverse (120305661), we get a palindrome (286808682).

The spelling of 166503021 in words is "one hundred sixty-six million, five hundred three thousand, twenty-one".