646140643 has 2 divisors, whose sum is σ = 646140644. Its totient is φ = 646140642.

The previous prime is 646140617. The next prime is 646140707. The reversal of 646140643 is 346041646.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646140643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 646140599 and 646140608.

It is not a weakly prime, because it can be changed into another prime (646140613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323070321 + 323070322.

It is an arithmetic number, because the mean of its divisors is an integer number (323070322).

Almost surely, 2^646140643 is an apocalyptic number.

646140643 is a deficient number, since it is larger than the sum of its proper divisors (1).

646140643 is an equidigital number, since it uses as much as digits as its factorization.

646140643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 34.

The square root of 646140643 is about 25419.2966661157. The cubic root of 646140643 is about 864.5212774231.

The spelling of 646140643 in words is "six hundred forty-six million, one hundred forty thousand, six hundred forty-three".