645443604 has 144 divisors (see below), whose sum is σ = 1914057600. Its totient is φ = 181585152.

The previous prime is 645443597. The next prime is 645443627. The reversal of 645443604 is 406344546.

645443604 is a `hidden beast` number, since 6 + 4 + 5 + 4 + 43 + 604 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 256617 + ... + 259119.

Almost surely, 2^645443604 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 645443604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (957028800).

645443604 is an abundant number, since it is smaller than the sum of its proper divisors (1268613996).

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

645443604 is a wasteful number, since it uses less digits than its factorization.

645443604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2574 (or 2569 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 36.

The square root of 645443604 is about 25405.5821425135. The cubic root of 645443604 is about 864.2102915336.

The spelling of 645443604 in words is "six hundred forty-five million, four hundred forty-three thousand, six hundred four".