645975792 has 480 divisors, whose sum is σ = 2506982400. Its totient is φ = 150036480.

The previous prime is 645975767. The next prime is 645975797. The reversal of 645975792 is 297579546.

645975792 is a `hidden beast` number, since 64 + 5 + 9 + 7 + 579 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645975797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4335334 + ... + 4335482.

It is an arithmetic number, because the mean of its divisors is an integer number (5222880).

Almost surely, 2^645975792 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 645975792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1253491200).

645975792 is an abundant number, since it is smaller than the sum of its proper divisors (1861006608).

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

645975792 is a wasteful number, since it uses less digits than its factorization.

645975792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 212 counting only the distinct ones).

The product of its digits is 4762800, while the sum is 54.

The square root of 645975792 is about 25416.0538243056. The cubic root of 645975792 is about 864.4477488910.

The spelling of 645975792 in words is "six hundred forty-five million, nine hundred seventy-five thousand, seven hundred ninety-two".