643532651651 has 2 divisors, whose sum is σ = 643532651652. Its totient is φ = 643532651650.

The previous prime is 643532651627. The next prime is 643532651693. The reversal of 643532651651 is 156156235346.

643532651651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643532651651 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643532651596 and 643532651605.

It is not a weakly prime, because it can be changed into another prime (643532656651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321766325825 + 321766325826.

It is an arithmetic number, because the mean of its divisors is an integer number (321766325826).

Almost surely, 2^643532651651 is an apocalyptic number.

643532651651 is a deficient number, since it is larger than the sum of its proper divisors (1).

643532651651 is an equidigital number, since it uses as much as digits as its factorization.

643532651651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944000, while the sum is 47.

Adding to 643532651651 its reverse (156156235346), we get a palindrome (799688886997).

The spelling of 643532651651 in words is "six hundred forty-three billion, five hundred thirty-two million, six hundred fifty-one thousand, six hundred fifty-one".