643577440 has 48 divisors (see below), whose sum is σ = 1658679120. Its totient is φ = 234027520.

The previous prime is 643577437. The next prime is 643577447. The reversal of 643577440 is 44775346.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 643577393 and 643577402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643577447) 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 7 ways as a sum of consecutive naturals, for example, 181075 + ... + 184594.

It is an arithmetic number, because the mean of its divisors is an integer number (34555815).

Almost surely, 2^643577440 is an apocalyptic number.

It is an amenable number.

643577440 is an abundant number, since it is smaller than the sum of its proper divisors (1015101680).

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

643577440 is a wasteful number, since it uses less digits than its factorization.

643577440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365695 (or 365687 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 40.

The square root of 643577440 is about 25368.8281164109. The cubic root of 643577440 is about 863.3765936228.

The spelling of 643577440 in words is "six hundred forty-three million, five hundred seventy-seven thousand, four hundred forty".