166666638 has 16 divisors (see below), whose sum is σ = 336284496. Its totient is φ = 55063680.

The previous prime is 166666637. The next prime is 166666639. The reversal of 166666638 is 836666661.

It is an interprime number because it is at equal distance from previous prime (166666637) and next prime (166666639).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166666631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122233 + ... + 123588.

It is an arithmetic number, because the mean of its divisors is an integer number (21017781).

Almost surely, 2^166666638 is an apocalyptic number.

166666638 is an abundant number, since it is smaller than the sum of its proper divisors (169617858).

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

166666638 is a wasteful number, since it uses less digits than its factorization.

166666638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245939.

The product of its digits is 1119744, while the sum is 48.

The square root of 166666638 is about 12909.9433771028. The cubic root of 166666638 is about 550.3211765974.

The spelling of 166666638 in words is "one hundred sixty-six million, six hundred sixty-six thousand, six hundred thirty-eight".