217705972 has 12 divisors (see below), whose sum is σ = 415620576. Its totient is φ = 98957240.

The previous prime is 217705937. The next prime is 217705991. The reversal of 217705972 is 279507712.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2473888 + ... + 2473975.

It is an arithmetic number, because the mean of its divisors is an integer number (34635048).

Almost surely, 2^217705972 is an apocalyptic number.

217705972 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

217705972 is a deficient number, since it is larger than the sum of its proper divisors (197914604).

217705972 is a wasteful number, since it uses less digits than its factorization.

217705972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4947878 (or 4947876 counting only the distinct ones).

The product of its (nonzero) digits is 61740, while the sum is 40.

The square root of 217705972 is about 14754.8626560873. The cubic root of 217705972 is about 601.5754632754.

Adding to 217705972 its product of nonzero digits (61740), we get a palindrome (217767712).

The spelling of 217705972 in words is "two hundred seventeen million, seven hundred five thousand, nine hundred seventy-two".