646622749 has 2 divisors, whose sum is σ = 646622750. Its totient is φ = 646622748.

The previous prime is 646622747. The next prime is 646622789. The reversal of 646622749 is 947226646.

646622749 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 can be written as a sum of positive squares in only one way, i.e., 575760025 + 70862724 = 23995^2 + 8418^2 .

It is a cyclic number.

It is not a de Polignac number, because 646622749 - 2¹ = 646622747 is a prime.

Together with 646622747, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 646622699 and 646622708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646622747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323311374 + 323311375.

It is an arithmetic number, because the mean of its divisors is an integer number (323311375).

Almost surely, 2^646622749 is an apocalyptic number.

It is an amenable number.

646622749 is a deficient number, since it is larger than the sum of its proper divisors (1).

646622749 is an equidigital number, since it uses as much as digits as its factorization.

646622749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 46.

The square root of 646622749 is about 25428.7779690649. Note that the first 3 decimals coincide. The cubic root of 646622749 is about 864.7362395381.

The spelling of 646622749 in words is "six hundred forty-six million, six hundred twenty-two thousand, seven hundred forty-nine".