646863823 has 2 divisors, whose sum is σ = 646863824. Its totient is φ = 646863822.

The previous prime is 646863817. The next prime is 646863827. The reversal of 646863823 is 328368646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646863823 - 2²¹ = 644766671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646863827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323431911 + 323431912.

It is an arithmetic number, because the mean of its divisors is an integer number (323431912).

Almost surely, 2^646863823 is an apocalyptic number.

646863823 is a deficient number, since it is larger than the sum of its proper divisors (1).

646863823 is an equidigital number, since it uses as much as digits as its factorization.

646863823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 46.

The square root of 646863823 is about 25433.5177079381. The cubic root of 646863823 is about 864.8436898885.

The spelling of 646863823 in words is "six hundred forty-six million, eight hundred sixty-three thousand, eight hundred twenty-three".