643504819 has 2 divisors, whose sum is σ = 643504820. Its totient is φ = 643504818.

The previous prime is 643504801. The next prime is 643504831. The reversal of 643504819 is 918405346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643504819 - 2¹¹ = 643502771 is a prime.

It is a super-2 number, since 2×643504819² = 828196904152445522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (643504319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321752409 + 321752410.

It is an arithmetic number, because the mean of its divisors is an integer number (321752410).

Almost surely, 2^643504819 is an apocalyptic number.

643504819 is a deficient number, since it is larger than the sum of its proper divisors (1).

643504819 is an equidigital number, since it uses as much as digits as its factorization.

643504819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 643504819 is about 25367.3967722350. The cubic root of 643504819 is about 863.3441180541.

It can be divided in two parts, 64350 and 4819, that added together give a square (69169 = 263²).

The spelling of 643504819 in words is "six hundred forty-three million, five hundred four thousand, eight hundred nineteen".