645720705 has 48 divisors (see below), whose sum is σ = 1289293824. Its totient is φ = 292844160.

The previous prime is 645720701. The next prime is 645720739. The reversal of 645720705 is 507027546.

645720705 is a `hidden beast` number, since 645 + 7 + 2 + 0 + 7 + 0 + 5 = 666.

645720705 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645720705 - 2² = 645720701 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645720705.

It is not an unprimeable number, because it can be changed into a prime (645720701) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 31935 + ... + 48075.

It is an arithmetic number, because the mean of its divisors is an integer number (26860288).

Almost surely, 2^645720705 is an apocalyptic number.

It is an amenable number.

645720705 is a deficient number, since it is larger than the sum of its proper divisors (643573119).

645720705 is a wasteful number, since it uses less digits than its factorization.

645720705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16286 (or 16283 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 36.

The square root of 645720705 is about 25411.0351028839. The cubic root of 645720705 is about 864.3339477149. Note that the first 3 decimals are identical.

The spelling of 645720705 in words is "six hundred forty-five million, seven hundred twenty thousand, seven hundred five".