645820067 has 2 divisors, whose sum is σ = 645820068. Its totient is φ = 645820066.

The previous prime is 645820057. The next prime is 645820079. The reversal of 645820067 is 760028546.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645820067 - 2⁶ = 645820003 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645820067.

It is not a weakly prime, because it can be changed into another prime (645820057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322910033 + 322910034.

It is an arithmetic number, because the mean of its divisors is an integer number (322910034).

Almost surely, 2^645820067 is an apocalyptic number.

645820067 is a deficient number, since it is larger than the sum of its proper divisors (1).

645820067 is an equidigital number, since it uses as much as digits as its factorization.

645820067 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 38.

The square root of 645820067 is about 25412.9901231634. The cubic root of 645820067 is about 864.3782793402.

The spelling of 645820067 in words is "six hundred forty-five million, eight hundred twenty thousand, sixty-seven".