218123906 has 144 divisors (see below), whose sum is σ = 485403840. Its totient is φ = 71285760.

The previous prime is 218123869. The next prime is 218123909. The reversal of 218123906 is 609321812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218123909) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 7521500 + ... + 7521528.

It is an arithmetic number, because the mean of its divisors is an integer number (3370860).

Almost surely, 2^218123906 is an apocalyptic number.

218123906 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

218123906 is an abundant number, since it is smaller than the sum of its proper divisors (267279934).

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

218123906 is a wasteful number, since it uses less digits than its factorization.

218123906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 79 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 218123906 is about 14769.0184507976. The cubic root of 218123906 is about 601.9601688859.

The spelling of 218123906 in words is "two hundred eighteen million, one hundred twenty-three thousand, nine hundred six".