643640067040 has 24 divisors (see below), whose sum is σ = 1520599658760. Its totient is φ = 257456026752.

The previous prime is 643640067013. The next prime is 643640067067. The reversal of 643640067040 is 40760046346.

It is an interprime number because it is at equal distance from previous prime (643640067013) and next prime (643640067067).

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 = 643640066984 and 643640067002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2011375050 + ... + 2011375369.

It is an arithmetic number, because the mean of its divisors is an integer number (63358319115).

Almost surely, 2^643640067040 is an apocalyptic number.

It is an amenable number.

643640067040 is an abundant number, since it is smaller than the sum of its proper divisors (876959591720).

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

643640067040 is a wasteful number, since it uses less digits than its factorization.

643640067040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4022750434 (or 4022750426 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 40.

The spelling of 643640067040 in words is "six hundred forty-three billion, six hundred forty million, sixty-seven thousand, forty".