645671040 has 192 divisors, whose sum is σ = 2394437760. Its totient is φ = 147560448.

The previous prime is 645671021. The next prime is 645671077. The reversal of 645671040 is 40176546.

It is a tau number, because it is divible by the number of its divisors (192).

It is a junction number, because it is equal to n+sod(n) for n = 645670992 and 645671010.

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 23 ways as a sum of consecutive naturals, for example, 90649 + ... + 97511.

It is an arithmetic number, because the mean of its divisors is an integer number (12471030).

Almost surely, 2^645671040 is an apocalyptic number.

645671040 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 645671040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1197218880).

645671040 is an abundant number, since it is smaller than the sum of its proper divisors (1748766720).

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

645671040 is a wasteful number, since it uses less digits than its factorization.

645671040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6899 (or 6880 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 645671040 is about 25410.0578511738. The cubic root of 645671040 is about 864.3117873362.

The spelling of 645671040 in words is "six hundred forty-five million, six hundred seventy-one thousand, forty".