645143200 has 288 divisors, whose sum is σ = 1860349680. Its totient is φ = 216268800.

The previous prime is 645143179. The next prime is 645143209. The reversal of 645143200 is 2341546.

It can be written as a sum of positive squares in 24 ways, for example, as 228493456 + 416649744 = 15116^2 + 20412^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (645143209) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7248756 + ... + 7248844.

Almost surely, 2^645143200 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645143200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (930174840).

645143200 is an abundant number, since it is smaller than the sum of its proper divisors (1215206480).

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

645143200 is a wasteful number, since it uses less digits than its factorization.

645143200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 645143200 is about 25399.6692891856. The cubic root of 645143200 is about 864.0761964122.

Adding to 645143200 its reverse (2341546), we get a palindrome (647484746).

The spelling of 645143200 in words is "six hundred forty-five million, one hundred forty-three thousand, two hundred".