643498968643 has 4 divisors (see below), whose sum is σ = 644499745288. Its totient is φ = 642498192000.

The previous prime is 643498968613. The next prime is 643498968647. The reversal of 643498968643 is 346869894346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643498968643 - 2¹³ = 643498960451 is a prime.

It is a super-2 number, since 2×643498968643² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643498968647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 500387358 + ... + 500388643.

It is an arithmetic number, because the mean of its divisors is an integer number (161124936322).

Almost surely, 2^643498968643 is an apocalyptic number.

643498968643 is a deficient number, since it is larger than the sum of its proper divisors (1000776645).

643498968643 is a wasteful number, since it uses less digits than its factorization.

643498968643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000776644.

The product of its digits is 644972544, while the sum is 70.

The spelling of 643498968643 in words is "six hundred forty-three billion, four hundred ninety-eight million, nine hundred sixty-eight thousand, six hundred forty-three".