645789726 has 32 divisors (see below), whose sum is σ = 1448513280. Its totient is φ = 213249528.

The previous prime is 645789707. The next prime is 645789731. The reversal of 645789726 is 627987546.

645789726 is a `hidden beast` number, since 64 + 578 + 9 + 7 + 2 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50106 + ... + 61661.

It is an arithmetic number, because the mean of its divisors is an integer number (45266040).

Almost surely, 2^645789726 is an apocalyptic number.

645789726 is an abundant number, since it is smaller than the sum of its proper divisors (802723554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645789726 is a wasteful number, since it uses less digits than its factorization.

645789726 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111885 (or 111879 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 54.

The square root of 645789726 is about 25412.3931576701. The cubic root of 645789726 is about 864.3647427978.

The spelling of 645789726 in words is "six hundred forty-five million, seven hundred eighty-nine thousand, seven hundred twenty-six".