645605678 has 8 divisors (see below), whose sum is σ = 969079368. Its totient is φ = 322579224.

The previous prime is 645605657. The next prime is 645605683. The reversal of 645605678 is 876506546.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108176 + ... + 113987.

It is an arithmetic number, because the mean of its divisors is an integer number (121134921).

Almost surely, 2^645605678 is an apocalyptic number.

645605678 is a deficient number, since it is larger than the sum of its proper divisors (323473690).

645605678 is a wasteful number, since it uses less digits than its factorization.

645605678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223618.

The product of its (nonzero) digits is 1209600, while the sum is 47.

The square root of 645605678 is about 25408.7716743647. The cubic root of 645605678 is about 864.2826212697.

The spelling of 645605678 in words is "six hundred forty-five million, six hundred five thousand, six hundred seventy-eight".