645222 has 16 divisors (see below), whose sum is σ = 1315440. Its totient is φ = 210912.

The previous prime is 645187. The next prime is 645233. The reversal of 645222 is 222546.

645222 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×645222² = 832622858568, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 697 + ... + 1332.

It is an arithmetic number, because the mean of its divisors is an integer number (82215).

2⁶⁴⁵²²² is an apocalyptic number.

645222 is an abundant number, since it is smaller than the sum of its proper divisors (670218).

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

645222 is a wasteful number, since it uses less digits than its factorization.

645222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2087.

The product of its digits is 960, while the sum is 21.

The square root of 645222 is about 803.2571194829. The cubic root of 645222 is about 86.4111375389.

Adding to 645222 its reverse (222546), we get a palindrome (867768).

The spelling of 645222 in words is "six hundred forty-five thousand, two hundred twenty-two".