645022656 has 112 divisors (see below), whose sum is σ = 1904390400. Its totient is φ = 214085376.

The previous prime is 645022627. The next prime is 645022681. The reversal of 645022656 is 656220546.

645022656 is a `hidden beast` number, since 645 + 0 + 2 + 2 + 6 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 645022656.

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, 488365 + ... + 489683.

Almost surely, 2^645022656 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 645022656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (952195200).

645022656 is an abundant number, since it is smaller than the sum of its proper divisors (1259367744).

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

645022656 is a wasteful number, since it uses less digits than its factorization.

645022656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1623 (or 1607 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 645022656 is about 25397.2962340482. The cubic root of 645022656 is about 864.0223759637.

The spelling of 645022656 in words is "six hundred forty-five million, twenty-two thousand, six hundred fifty-six".