643500667 has 2 divisors, whose sum is σ = 643500668. Its totient is φ = 643500666.

The previous prime is 643500659. The next prime is 643500673. The reversal of 643500667 is 766005346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643500667 - 2³ = 643500659 is a prime.

It is not a weakly prime, because it can be changed into another prime (643500367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321750333 + 321750334.

It is an arithmetic number, because the mean of its divisors is an integer number (321750334).

Almost surely, 2^643500667 is an apocalyptic number.

643500667 is a deficient number, since it is larger than the sum of its proper divisors (1).

643500667 is an equidigital number, since it uses as much as digits as its factorization.

643500667 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 37.

The square root of 643500667 is about 25367.3149347738. The cubic root of 643500667 is about 863.3422612368.

The spelling of 643500667 in words is "six hundred forty-three million, five hundred thousand, six hundred sixty-seven".