217122066 has 64 divisors (see below), whose sum is σ = 553512960. Its totient is φ = 61799760.

The previous prime is 217122053. The next prime is 217122067. The reversal of 217122066 is 660221712.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (217122067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 115111 + ... + 116981.

It is an arithmetic number, because the mean of its divisors is an integer number (8648640).

Almost surely, 2^217122066 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217122066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276756480).

217122066 is an abundant number, since it is smaller than the sum of its proper divisors (336390894).

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

217122066 is a wasteful number, since it uses less digits than its factorization.

217122066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196 (or 2190 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 217122066 is about 14735.0624701764. The cubic root of 217122066 is about 601.0371561455.

Adding to 217122066 its reverse (660221712), we get a palindrome (877343778).

The spelling of 217122066 in words is "two hundred seventeen million, one hundred twenty-two thousand, sixty-six".