645504444 has 96 divisors (see below), whose sum is σ = 1860526080. Its totient is φ = 192196800.

The previous prime is 645504397. The next prime is 645504469. The reversal of 645504444 is 444405546.

645504444 is a `hidden beast` number, since 64 + 550 + 4 + 4 + 44 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 645504399 and 645504408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36109 + ... + 50939.

It is an arithmetic number, because the mean of its divisors is an integer number (19380480).

Almost surely, 2^645504444 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 645504444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (930263040).

645504444 is an abundant number, since it is smaller than the sum of its proper divisors (1215021636).

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

645504444 is a wasteful number, since it uses less digits than its factorization.

645504444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14888 (or 14880 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 36.

The square root of 645504444 is about 25406.7794889474. The cubic root of 645504444 is about 864.2374443846.

The spelling of 645504444 in words is "six hundred forty-five million, five hundred four thousand, four hundred forty-four".