645708672 has 480 divisors, whose sum is σ = 2363739840. Its totient is φ = 174182400.

The previous prime is 645708667. The next prime is 645708677. The reversal of 645708672 is 276807546.

645708672 is a `hidden beast` number, since 6 + 4 + 570 + 8 + 6 + 72 = 666.

645708672 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (645708667) and next prime (645708677).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645708677) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 15748972 + ... + 15749012.

It is an arithmetic number, because the mean of its divisors is an integer number (4924458).

Almost surely, 2^645708672 is an apocalyptic number.

645708672 is a gapful number since it is divisible by the number (62) 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 645708672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1181869920).

645708672 is an abundant number, since it is smaller than the sum of its proper divisors (1718031168).

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

645708672 is a wasteful number, since it uses less digits than its factorization.

645708672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The square root of 645708672 is about 25410.7983345664. The cubic root of 645708672 is about 864.3285787296.

The spelling of 645708672 in words is "six hundred forty-five million, seven hundred eight thousand, six hundred seventy-two".