645354370444 has 216 divisors, whose sum is σ = 1399835691072. Its totient is φ = 259401139200.

The previous prime is 645354370421. The next prime is 645354370457. The reversal of 645354370444 is 444073453546.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 920619294 + ... + 920619994.

It is an arithmetic number, because the mean of its divisors is an integer number (6480720792).

Almost surely, 2^645354370444 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 645354370444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (699917845536).

645354370444 is an abundant number, since it is smaller than the sum of its proper divisors (754481320628).

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

645354370444 is a wasteful number, since it uses less digits than its factorization.

645354370444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913 (or 867 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 49.

The spelling of 645354370444 in words is "six hundred forty-five billion, three hundred fifty-four million, three hundred seventy thousand, four hundred forty-four".