645720630 has 32 divisors (see below), whose sum is σ = 1617110784. Its totient is φ = 164705376.

The previous prime is 645720629. The next prime is 645720671. The reversal of 645720630 is 36027546.

It is a junction number, because it is equal to n+sod(n) for n = 645720591 and 645720600.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 467224 + ... + 468603.

It is an arithmetic number, because the mean of its divisors is an integer number (50534712).

Almost surely, 2^645720630 is an apocalyptic number.

645720630 is an abundant number, since it is smaller than the sum of its proper divisors (971390154).

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

645720630 is a wasteful number, since it uses less digits than its factorization.

645720630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935860.

The product of its (nonzero) digits is 30240, while the sum is 33.

The square root of 645720630 is about 25411.0336271471. The cubic root of 645720630 is about 864.3339142510. Note that the first 3 decimals are identical.

The spelling of 645720630 in words is "six hundred forty-five million, seven hundred twenty thousand, six hundred thirty".