643797923 has 2 divisors, whose sum is σ = 643797924. Its totient is φ = 643797922.

The previous prime is 643797901. The next prime is 643797953. The reversal of 643797923 is 329797346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643797923 - 2¹⁴ = 643781539 is a prime.

It is a super-2 number, since 2×643797923² = 828951531318227858, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (643797953) 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, 321898961 + 321898962.

It is an arithmetic number, because the mean of its divisors is an integer number (321898962).

Almost surely, 2^643797923 is an apocalyptic number.

643797923 is a deficient number, since it is larger than the sum of its proper divisors (1).

643797923 is an equidigital number, since it uses as much as digits as its factorization.

643797923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1714608, while the sum is 50.

The square root of 643797923 is about 25373.1732938551. The cubic root of 643797923 is about 863.4751770075.

The spelling of 643797923 in words is "six hundred forty-three million, seven hundred ninety-seven thousand, nine hundred twenty-three".