644173464 has 64 divisors (see below), whose sum is σ = 1770762240. Its totient is φ = 193656960.

The previous prime is 644173463. The next prime is 644173507. The reversal of 644173464 is 464371446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644173463) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23922 + ... + 43134.

It is an arithmetic number, because the mean of its divisors is an integer number (27668160).

Almost surely, 2^644173464 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 644173464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885381120).

644173464 is an abundant number, since it is smaller than the sum of its proper divisors (1126588776).

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

644173464 is a wasteful number, since it uses less digits than its factorization.

644173464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19360 (or 19356 counting only the distinct ones).

The product of its digits is 193536, while the sum is 39.

The square root of 644173464 is about 25380.5725703736. The cubic root of 644173464 is about 863.6430388417.

The spelling of 644173464 in words is "six hundred forty-four million, one hundred seventy-three thousand, four hundred sixty-four".