645913926 has 96 divisors (see below), whose sum is σ = 1716099840. Its totient is φ = 178155936.

The previous prime is 645913913. The next prime is 645913943. The reversal of 645913926 is 629319546.

645913926 is a `hidden beast` number, since 6 + 4 + 591 + 39 + 26 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 95385 + ... + 101931.

It is an arithmetic number, because the mean of its divisors is an integer number (17876040).

Almost surely, 2^645913926 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645913926, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (858049920).

645913926 is an abundant number, since it is smaller than the sum of its proper divisors (1070185914).

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

645913926 is a wasteful number, since it uses less digits than its factorization.

645913926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6600 (or 6588 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 645913926 is about 25414.8367297530. The cubic root of 645913926 is about 864.4201515556.

The spelling of 645913926 in words is "six hundred forty-five million, nine hundred thirteen thousand, nine hundred twenty-six".