645688934 has 16 divisors (see below), whose sum is σ = 1118734416. Its totient is φ = 276230400.

The previous prime is 645688921. The next prime is 645688937. The reversal of 645688934 is 439886546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645688937) 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 7 ways as a sum of consecutive naturals, for example, 862847 + ... + 863594.

It is an arithmetic number, because the mean of its divisors is an integer number (69920901).

Almost surely, 2^645688934 is an apocalyptic number.

645688934 is a deficient number, since it is larger than the sum of its proper divisors (473045482).

645688934 is a wasteful number, since it uses less digits than its factorization.

645688934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726471.

The product of its digits is 4976640, while the sum is 53.

The square root of 645688934 is about 25410.4099534030. The cubic root of 645688934 is about 864.3197717179.

The spelling of 645688934 in words is "six hundred forty-five million, six hundred eighty-eight thousand, nine hundred thirty-four".