645443641 has 12 divisors (see below), whose sum is σ = 715462272. Its totient is φ = 581058368.

The previous prime is 645443627. The next prime is 645443671. The reversal of 645443641 is 146344546.

It is not a de Polignac number, because 645443641 - 2¹¹ = 645441593 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645443641.

It is not an unprimeable number, because it can be changed into a prime (645443671) 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, 41905 + ... + 55198.

It is an arithmetic number, because the mean of its divisors is an integer number (59621856).

Almost surely, 2^645443641 is an apocalyptic number.

It is an amenable number.

645443641 is a deficient number, since it is larger than the sum of its proper divisors (70018631).

645443641 is a wasteful number, since it uses less digits than its factorization.

645443641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97160 (or 97143 counting only the distinct ones).

The product of its digits is 138240, while the sum is 37.

The square root of 645443641 is about 25405.5828706999. The cubic root of 645443641 is about 864.2103080472.

The spelling of 645443641 in words is "six hundred forty-five million, four hundred forty-three thousand, six hundred forty-one".