640378073 has 2 divisors, whose sum is σ = 640378074. Its totient is φ = 640378072.

The previous prime is 640378021. The next prime is 640378091. The reversal of 640378073 is 370873046.

640378073 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 399880009 + 240498064 = 19997^2 + 15508^2 .

It is a cyclic number.

It is not a de Polignac number, because 640378073 - 2⁶ = 640378009 is a prime.

It is not a weakly prime, because it can be changed into another prime (640378373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320189036 + 320189037.

It is an arithmetic number, because the mean of its divisors is an integer number (320189037).

Almost surely, 2^640378073 is an apocalyptic number.

It is an amenable number.

640378073 is a deficient number, since it is larger than the sum of its proper divisors (1).

640378073 is an equidigital number, since it uses as much as digits as its factorization.

640378073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84672, while the sum is 38.

The square root of 640378073 is about 25305.6925018858. The cubic root of 640378073 is about 861.9435371059.

The spelling of 640378073 in words is "six hundred forty million, three hundred seventy-eight thousand, seventy-three".