643124640 has 48 divisors (see below), whose sum is σ = 2025844128. Its totient is φ = 171499776.

The previous prime is 643124633. The next prime is 643124653. The reversal of 643124640 is 46421346.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 643124598 and 643124607.

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, 669442 + ... + 670401.

It is an arithmetic number, because the mean of its divisors is an integer number (42205086).

Almost surely, 2^643124640 is an apocalyptic number.

643124640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643124640 is an abundant number, since it is smaller than the sum of its proper divisors (1382719488).

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

643124640 is a wasteful number, since it uses less digits than its factorization.

643124640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1339861 (or 1339853 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 643124640 is about 25359.9022080133. The cubic root of 643124640 is about 863.1740649569.

Adding to 643124640 its reverse (46421346), we get a palindrome (689545986).

The spelling of 643124640 in words is "six hundred forty-three million, one hundred twenty-four thousand, six hundred forty".