645522 has 16 divisors (see below), whose sum is σ = 1299072. Its totient is φ = 213840.

The previous prime is 645521. The next prime is 645527. The reversal of 645522 is 225546.

645522 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 645492 and 645501.

It is not an unprimeable number, because it can be changed into a prime (645521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1428 + ... + 1824.

It is an arithmetic number, because the mean of its divisors is an integer number (81192).

2⁶⁴⁵⁵²² is an apocalyptic number.

645522 is an abundant number, since it is smaller than the sum of its proper divisors (653550).

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

645522 is a wasteful number, since it uses less digits than its factorization.

645522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673.

The product of its digits is 2400, while the sum is 24.

The square root of 645522 is about 803.4438374896. The cubic root of 645522 is about 86.4245279298.

Adding to 645522 its sum of digits (24), we get a palindrome (645546).

The spelling of 645522 in words is "six hundred forty-five thousand, five hundred twenty-two".