212181606 has 160 divisors (see below), whose sum is σ = 602521920. Its totient is φ = 54307584.

The previous prime is 212181589. The next prime is 212181611. The reversal of 212181606 is 606181212.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 212181606.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 545260 + ... + 545648.

It is an arithmetic number, because the mean of its divisors is an integer number (3765762).

Almost surely, 2^212181606 is an apocalyptic number.

212181606 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 212181606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301260960).

212181606 is an abundant number, since it is smaller than the sum of its proper divisors (390340314).

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

212181606 is a wasteful number, since it uses less digits than its factorization.

212181606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460 (or 451 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 212181606 is about 14566.4548192070. The cubic root of 212181606 is about 596.4434094285.

The spelling of 212181606 in words is "two hundred twelve million, one hundred eighty-one thousand, six hundred six".