644062480 has 40 divisors (see below), whose sum is σ = 1500183000. Its totient is φ = 257154048.

The previous prime is 644062469. The next prime is 644062499. The reversal of 644062480 is 84260446.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 99680256 + 544382224 = 9984^2 + 23332^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 38446 + ... + 52594.

It is an arithmetic number, because the mean of its divisors is an integer number (37504575).

Almost surely, 2^644062480 is an apocalyptic number.

It is an amenable number.

644062480 is an abundant number, since it is smaller than the sum of its proper divisors (856120520).

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

644062480 is a wasteful number, since it uses less digits than its factorization.

644062480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14731 (or 14725 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 34.

The square root of 644062480 is about 25378.3860794969. The cubic root of 644062480 is about 863.5934372620.

The spelling of 644062480 in words is "six hundred forty-four million, sixty-two thousand, four hundred eighty".