221706212 has 48 divisors (see below), whose sum is σ = 502669440. Its totient is φ = 83089152.

The previous prime is 221706181. The next prime is 221706217. The reversal of 221706212 is 212607122.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (221706217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9113 + ... + 22944.

It is an arithmetic number, because the mean of its divisors is an integer number (10472280).

Almost surely, 2^221706212 is an apocalyptic number.

It is an amenable number.

221706212 is an abundant number, since it is smaller than the sum of its proper divisors (280963228).

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

221706212 is a wasteful number, since it uses less digits than its factorization.

221706212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32100 (or 32098 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 221706212 is about 14889.8022820990. The cubic root of 221706212 is about 605.2376745293.

It can be divided in two parts, 22170 and 6212, that added together give a palindrome (28382).

The spelling of 221706212 in words is "two hundred twenty-one million, seven hundred six thousand, two hundred twelve".