645719256 has 432 divisors, whose sum is σ = 2384526600. Its totient is φ = 161336448.

The previous prime is 645719231. The next prime is 645719317. The reversal of 645719256 is 652917546.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

645719256 is a `hidden beast` number, since 6 + 457 + 192 + 5 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 33985215 + ... + 33985233.

Almost surely, 2^645719256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645719256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1192263300).

645719256 is an abundant number, since it is smaller than the sum of its proper divisors (1738807344).

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

645719256 is a wasteful number, since it uses less digits than its factorization.

645719256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 44 counting only the distinct ones).

The product of its digits is 453600, while the sum is 45.

The square root of 645719256 is about 25411.0065916327. The cubic root of 645719256 is about 864.3333011914. Note that the first 4 decimals are identical.

The spelling of 645719256 in words is "six hundred forty-five million, seven hundred nineteen thousand, two hundred fifty-six".