646433927549 has 2 divisors, whose sum is σ = 646433927550. Its totient is φ = 646433927548.

The previous prime is 646433927543. The next prime is 646433927593. The reversal of 646433927549 is 945729334646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 577524002500 + 68909925049 = 759950^2 + 262507^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646433927549 is a prime.

It is a super-2 number, since 2×646433927549² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 646433927491 and 646433927500.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646433927543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323216963774 + 323216963775.

It is an arithmetic number, because the mean of its divisors is an integer number (323216963775).

Almost surely, 2^646433927549 is an apocalyptic number.

It is an amenable number.

646433927549 is a deficient number, since it is larger than the sum of its proper divisors (1).

646433927549 is an equidigital number, since it uses as much as digits as its factorization.

646433927549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 117573120, while the sum is 62.

The spelling of 646433927549 in words is "six hundred forty-six billion, four hundred thirty-three million, nine hundred twenty-seven thousand, five hundred forty-nine".