645813603 has 24 divisors (see below), whose sum is σ = 968821568. Its totient is φ = 414236592.

The previous prime is 645813583. The next prime is 645813617. The reversal of 645813603 is 306318546.

645813603 is a `hidden beast` number, since 6 + 45 + 8 + 1 + 3 + 603 = 666.

It is not a de Polignac number, because 645813603 - 2¹⁶ = 645748067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645813653) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 13476 + ... + 38382.

Almost surely, 2^645813603 is an apocalyptic number.

645813603 is a deficient number, since it is larger than the sum of its proper divisors (323007965).

645813603 is a wasteful number, since it uses less digits than its factorization.

645813603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25023 (or 25020 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 645813603 is about 25412.8629437929. The cubic root of 645813603 is about 864.3753954823.

It can be divided in two parts, 645813 and 603, that added together give a square (646416 = 804²).

The spelling of 645813603 in words is "six hundred forty-five million, eight hundred thirteen thousand, six hundred three".