645865948 has 72 divisors (see below), whose sum is σ = 1433285280. Its totient is φ = 249200640.

The previous prime is 645865943. The next prime is 645865949. The reversal of 645865948 is 849568546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645865943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 192348 + ... + 195676.

It is an arithmetic number, because the mean of its divisors is an integer number (19906740).

Almost surely, 2^645865948 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 645865948, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (716642640).

645865948 is an abundant number, since it is smaller than the sum of its proper divisors (787419332).

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

645865948 is a wasteful number, since it uses less digits than its factorization.

645865948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3407 (or 3392 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 55.

The square root of 645865948 is about 25413.8928147578. The cubic root of 645865948 is about 864.3987481997.

The spelling of 645865948 in words is "six hundred forty-five million, eight hundred sixty-five thousand, nine hundred forty-eight".