643402544 has 40 divisors (see below), whose sum is σ = 1271109120. Its totient is φ = 315432000.

The previous prime is 643402517. The next prime is 643402589. The reversal of 643402544 is 445204346.

It is a self number, because there is not a number n which added to its sum of digits gives 643402544.

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, 189179 + ... + 192549.

It is an arithmetic number, because the mean of its divisors is an integer number (31777728).

Almost surely, 2^643402544 is an apocalyptic number.

It is an amenable number.

643402544 is a deficient number, since it is larger than the sum of its proper divisors (627706576).

643402544 is a wasteful number, since it uses less digits than its factorization.

643402544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3609 (or 3603 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 32.

The square root of 643402544 is about 25365.3808171689. The cubic root of 643402544 is about 863.2983772943.

The spelling of 643402544 in words is "six hundred forty-three million, four hundred two thousand, five hundred forty-four".