166638481 has 4 divisors (see below), whose sum is σ = 166691952. Its totient is φ = 166585012.

The previous prime is 166638469. The next prime is 166638499. The reversal of 166638481 is 184836661.

It is a happy number.

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 166638481 - 2⁹ = 166637969 is a prime.

It is a super-2 number, since 2×166638481² = 55536766699974722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166638181) 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, 21751 + ... + 28396.

It is an arithmetic number, because the mean of its divisors is an integer number (41672988).

Almost surely, 2^166638481 is an apocalyptic number.

It is an amenable number.

166638481 is a deficient number, since it is larger than the sum of its proper divisors (53471).

166638481 is an equidigital number, since it uses as much as digits as its factorization.

166638481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53470.

The product of its digits is 165888, while the sum is 43.

The square root of 166638481 is about 12908.8528150258. The cubic root of 166638481 is about 550.2901840599.

The spelling of 166638481 in words is "one hundred sixty-six million, six hundred thirty-eight thousand, four hundred eighty-one".