643503844621 has 16 divisors (see below), whose sum is σ = 732555394560. Its totient is φ = 559546195120.

The previous prime is 643503844603. The next prime is 643503844631. The reversal of 643503844621 is 126448305346.

It is not a de Polignac number, because 643503844621 - 2²⁵ = 643470290189 is a prime.

It is a super-2 number, since 2×643503844621² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643503844631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11225610 + ... + 11282788.

It is an arithmetic number, because the mean of its divisors is an integer number (45784712160).

Almost surely, 2^643503844621 is an apocalyptic number.

It is an amenable number.

643503844621 is a deficient number, since it is larger than the sum of its proper divisors (89051549939).

643503844621 is a wasteful number, since it uses less digits than its factorization.

643503844621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101696.

The product of its (nonzero) digits is 1658880, while the sum is 46.

The spelling of 643503844621 in words is "six hundred forty-three billion, five hundred three million, eight hundred forty-four thousand, six hundred twenty-one".