645965040 has 400 divisors, whose sum is σ = 2500732800. Its totient is φ = 137507328.

The previous prime is 645965027. The next prime is 645965057. The reversal of 645965040 is 40569546.

It is a self number, because there is not a number n which added to its sum of digits gives 645965040.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 10948531 + ... + 10948589.

It is an arithmetic number, because the mean of its divisors is an integer number (6251832).

Almost surely, 2^645965040 is an apocalyptic number.

645965040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645965040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1250366400).

645965040 is an abundant number, since it is smaller than the sum of its proper divisors (1854767760).

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

645965040 is a wasteful number, since it uses less digits than its factorization.

645965040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 39.

The square root of 645965040 is about 25415.8423035712. The cubic root of 645965040 is about 864.4429527393.

The spelling of 645965040 in words is "six hundred forty-five million, nine hundred sixty-five thousand, forty".