163666638 has 12 divisors (see below), whose sum is σ = 354611088. Its totient is φ = 54555540.

The previous prime is 163666631. The next prime is 163666673. The reversal of 163666638 is 836666361.

It is a happy number.

163666638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 163666593 and 163666602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163666631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4546278 + ... + 4546313.

It is an arithmetic number, because the mean of its divisors is an integer number (29550924).

Almost surely, 2^163666638 is an apocalyptic number.

163666638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

163666638 is an abundant number, since it is smaller than the sum of its proper divisors (190944450).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

163666638 is a wasteful number, since it uses less digits than its factorization.

163666638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9092599 (or 9092596 counting only the distinct ones).

The product of its digits is 559872, while the sum is 45.

The square root of 163666638 is about 12793.2262545458. The cubic root of 163666638 is about 546.9992368757. Note that the first 3 decimals are identical.

The spelling of 163666638 in words is "one hundred sixty-three million, six hundred sixty-six thousand, six hundred thirty-eight".