644448474 has 40 divisors (see below), whose sum is σ = 1455113088. Its totient is φ = 213169320.

The previous prime is 644448473. The next prime is 644448487. The reversal of 644448474 is 474844446.

644448474 is a `hidden beast` number, since 64 + 44 + 484 + 74 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644448473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6039 + ... + 36405.

Almost surely, 2^644448474 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644448474, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (727556544).

644448474 is an abundant number, since it is smaller than the sum of its proper divisors (810664614).

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

644448474 is a wasteful number, since it uses less digits than its factorization.

644448474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30512 (or 30503 counting only the distinct ones).

The product of its digits is 1376256, while the sum is 45.

The square root of 644448474 is about 25385.9897187405. The cubic root of 644448474 is about 863.7659232790.

The spelling of 644448474 in words is "six hundred forty-four million, four hundred forty-eight thousand, four hundred seventy-four".