166420906 has 4 divisors (see below), whose sum is σ = 249631362. Its totient is φ = 83210452.

The previous prime is 166420897. The next prime is 166420909. The reversal of 166420906 is 609024661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 609024661 = 7 ⋅87003523.

It can be written as a sum of positive squares in only one way, i.e., 128709025 + 37711881 = 11345^2 + 6141^2 .

It is not an unprimeable number, because it can be changed into a prime (166420909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41605225 + ... + 41605228.

Almost surely, 2^166420906 is an apocalyptic number.

166420906 is a deficient number, since it is larger than the sum of its proper divisors (83210456).

166420906 is an equidigital number, since it uses as much as digits as its factorization.

166420906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83210455.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 166420906 is about 12900.4227062527. The cubic root of 166420906 is about 550.0505804722.

The spelling of 166420906 in words is "one hundred sixty-six million, four hundred twenty thousand, nine hundred six".