645503403 has 16 divisors (see below), whose sum is σ = 876697856. Its totient is φ = 422353440.

The previous prime is 645503381. The next prime is 645503471. The reversal of 645503403 is 304305546.

It is not a de Polignac number, because 645503403 - 2¹² = 645499307 is a prime.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (645503003) 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 15 ways as a sum of consecutive naturals, for example, 85500 + ... + 92742.

It is an arithmetic number, because the mean of its divisors is an integer number (54793616).

Almost surely, 2^645503403 is an apocalyptic number.

645503403 is a deficient number, since it is larger than the sum of its proper divisors (231194453).

645503403 is a wasteful number, since it uses less digits than its factorization.

645503403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7794.

The product of its (nonzero) digits is 21600, while the sum is 30.

The square root of 645503403 is about 25406.7590022813. The cubic root of 645503403 is about 864.2369798014.

Adding to 645503403 its reverse (304305546), we get a palindrome (949808949).

The spelling of 645503403 in words is "six hundred forty-five million, five hundred three thousand, four hundred three".