646863829 has 2 divisors, whose sum is σ = 646863830. Its totient is φ = 646863828.

The previous prime is 646863827. The next prime is 646863851. The reversal of 646863829 is 928368646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 646684900 + 178929 = 25430^2 + 423^2 .

It is a cyclic number.

It is not a de Polignac number, because 646863829 - 2¹ = 646863827 is a prime.

Together with 646863827, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646863823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323431914 + 323431915.

It is an arithmetic number, because the mean of its divisors is an integer number (323431915).

Almost surely, 2^646863829 is an apocalyptic number.

It is an amenable number.

646863829 is a deficient number, since it is larger than the sum of its proper divisors (1).

646863829 is an equidigital number, since it uses as much as digits as its factorization.

646863829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2985984, while the sum is 52.

The square root of 646863829 is about 25433.5178258927. The cubic root of 646863829 is about 864.8436925625.

The spelling of 646863829 in words is "six hundred forty-six million, eight hundred sixty-three thousand, eight hundred twenty-nine".