646424279 has 2 divisors, whose sum is σ = 646424280. Its totient is φ = 646424278.

The previous prime is 646424243. The next prime is 646424287. The reversal of 646424279 is 972424646.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646424279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646424209) 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, 323212139 + 323212140.

It is an arithmetic number, because the mean of its divisors is an integer number (323212140).

Almost surely, 2^646424279 is an apocalyptic number.

646424279 is a deficient number, since it is larger than the sum of its proper divisors (1).

646424279 is an equidigital number, since it uses as much as digits as its factorization.

646424279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 44.

The square root of 646424279 is about 25424.8752012670. The cubic root of 646424279 is about 864.6477583932.

It can be divided in two parts, 64642 and 4279, that added together give a cube (68921 = 41³).

The spelling of 646424279 in words is "six hundred forty-six million, four hundred twenty-four thousand, two hundred seventy-nine".