166306021 has 16 divisors (see below), whose sum is σ = 193463424. Its totient is φ = 140019264.

The previous prime is 166306003. The next prime is 166306033. The reversal of 166306021 is 120603661.

166306021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 166306021 - 2⁵ = 166305989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166306001) 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, 113731 + ... + 115183.

It is an arithmetic number, because the mean of its divisors is an integer number (12091464).

Almost surely, 2^166306021 is an apocalyptic number.

It is an amenable number.

166306021 is a deficient number, since it is larger than the sum of its proper divisors (27157403).

166306021 is a wasteful number, since it uses less digits than its factorization.

166306021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1740.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 166306021 is about 12895.9691764520. The cubic root of 166306021 is about 549.9239795757.

Adding to 166306021 its reverse (120603661), we get a palindrome (286909682).

The spelling of 166306021 in words is "one hundred sixty-six million, three hundred six thousand, twenty-one".