645735040 has 64 divisors (see below), whose sum is σ = 1572919560. Its totient is φ = 253407232.

The previous prime is 645735037. The next prime is 645735047. The reversal of 645735040 is 40537546.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 373880896 + 271854144 = 19336^2 + 16488^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 645734987 and 645735005.

It is not an unprimeable number, because it can be changed into a prime (645735047) 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, 24402 + ... + 43438.

Almost surely, 2^645735040 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 645735040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786459780).

645735040 is an abundant number, since it is smaller than the sum of its proper divisors (927184520).

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

645735040 is a wasteful number, since it uses less digits than its factorization.

645735040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19109 (or 19097 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 34.

The square root of 645735040 is about 25411.3171638150. The cubic root of 645735040 is about 864.3403437389.

The spelling of 645735040 in words is "six hundred forty-five million, seven hundred thirty-five thousand, forty".