643440501 has 12 divisors (see below), whose sum is σ = 1013906400. Its totient is φ = 389963880.

The previous prime is 643440493. The next prime is 643440509. The reversal of 643440501 is 105044346.

It is an interprime number because it is at equal distance from previous prime (643440493) and next prime (643440509).

It is not a de Polignac number, because 643440501 - 2³ = 643440493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643440509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3249601 + ... + 3249798.

It is an arithmetic number, because the mean of its divisors is an integer number (84492200).

Almost surely, 2^643440501 is an apocalyptic number.

It is an amenable number.

643440501 is a deficient number, since it is larger than the sum of its proper divisors (370465899).

643440501 is a wasteful number, since it uses less digits than its factorization.

643440501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6499416 (or 6499413 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 643440501 is about 25366.1290109469. The cubic root of 643440501 is about 863.3153534847.

Adding to 643440501 its reverse (105044346), we get a palindrome (748484847).

It can be divided in two parts, 643 and 440501, that added together give a palindrome (441144).

The spelling of 643440501 in words is "six hundred forty-three million, four hundred forty thousand, five hundred one".