217212210 has 24 divisors (see below), whose sum is σ = 564751980. Its totient is φ = 57923232.

The previous prime is 217212181. The next prime is 217212211. The reversal of 217212210 is 12212712.

It is a happy number.

217212210 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 183792249 + 33419961 = 13557^2 + 5781^2 .

It is a super-2 number, since 2×217212210² = 94362288346168200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (217212211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1206645 + ... + 1206824.

Almost surely, 2^217212210 is an apocalyptic number.

217212210 is an abundant number, since it is smaller than the sum of its proper divisors (347539770).

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

217212210 is a wasteful number, since it uses less digits than its factorization.

217212210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413482 (or 2413479 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 217212210 is about 14738.1209792836. The cubic root of 217212210 is about 601.1203234901.

Adding to 217212210 its reverse (12212712), we get a palindrome (229424922).

The spelling of 217212210 in words is "two hundred seventeen million, two hundred twelve thousand, two hundred ten".