645210 has 48 divisors (see below), whose sum is σ = 1718496. Its totient is φ = 167904.

The previous prime is 645187. The next prime is 645233. The reversal of 645210 is 12546.

It is a happy number.

645210 is a `hidden beast` number, since 645 + 21 + 0 = 666.

645210 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (645187) and next prime (645233).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5977 + ... + 6083.

It is an arithmetic number, because the mean of its divisors is an integer number (35802).

2⁶⁴⁵²¹⁰ is an apocalyptic number.

645210 is the 402-nd decagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (859248).

645210 is an abundant number, since it is smaller than the sum of its proper divisors (1073286).

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

645210 is a wasteful number, since it uses less digits than its factorization.

645210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 645210 is about 803.2496498599. The cubic root of 645210 is about 86.4106018369.

Adding to 645210 its reverse (12546), we get a palindrome (657756).

The spelling of 645210 in words is "six hundred forty-five thousand, two hundred ten".