645646626 has 24 divisors (see below), whose sum is σ = 1450713264. Its totient is φ = 215215380.

The previous prime is 645646571. The next prime is 645646627. The reversal of 645646626 is 626646546.

645646626 is a `hidden beast` number, since 6 + 4 + 564 + 66 + 26 = 666.

645646626 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (645646627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 663760 + ... + 664731.

It is an arithmetic number, because the mean of its divisors is an integer number (60446386).

Almost surely, 2^645646626 is an apocalyptic number.

645646626 is an abundant number, since it is smaller than the sum of its proper divisors (805066638).

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

645646626 is a wasteful number, since it uses less digits than its factorization.

645646626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328508 (or 1328496 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 45.

The square root of 645646626 is about 25409.5774463095. The cubic root of 645646626 is about 864.3008934637.

The spelling of 645646626 in words is "six hundred forty-five million, six hundred forty-six thousand, six hundred twenty-six".