645224130 has 80 divisors (see below), whose sum is σ = 1781908920. Its totient is φ = 167401728.

The previous prime is 645224089. The next prime is 645224141. The reversal of 645224130 is 31422546.

645224130 is a `hidden beast` number, since 6 + 4 + 522 + 4 + 130 = 666.

645224130 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 4 ways, for example, as 537915249 + 107308881 = 23193^2 + 10359^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 645224094 and 645224103.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 19206 + ... + 40734.

Almost surely, 2^645224130 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645224130, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (890954460).

645224130 is an abundant number, since it is smaller than the sum of its proper divisors (1136684790).

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

645224130 is a wasteful number, since it uses less digits than its factorization.

645224130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21585 (or 21576 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 645224130 is about 25401.2623702051. The cubic root of 645224130 is about 864.1123262526.

Adding to 645224130 its reverse (31422546), we get a palindrome (676646676).

The spelling of 645224130 in words is "six hundred forty-five million, two hundred twenty-four thousand, one hundred thirty".