645974678 has 8 divisors (see below), whose sum is σ = 975379440. Its totient is φ = 320848200.

The previous prime is 645974677. The next prime is 645974699. The reversal of 645974678 is 876479546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645974677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1069193 + ... + 1069796.

It is an arithmetic number, because the mean of its divisors is an integer number (121922430).

Almost surely, 2^645974678 is an apocalyptic number.

645974678 is a deficient number, since it is larger than the sum of its proper divisors (329404762).

645974678 is a wasteful number, since it uses less digits than its factorization.

645974678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2139142.

The product of its digits is 10160640, while the sum is 56.

The square root of 645974678 is about 25416.0319090136. The cubic root of 645974678 is about 864.4472519708.

The spelling of 645974678 in words is "six hundred forty-five million, nine hundred seventy-four thousand, six hundred seventy-eight".