640332073 has 2 divisors, whose sum is σ = 640332074. Its totient is φ = 640332072.

The previous prime is 640331999. The next prime is 640332103. The reversal of 640332073 is 370233046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 515607849 + 124724224 = 22707^2 + 11168^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640332073 is a prime.

It is not a weakly prime, because it can be changed into another prime (640330073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320166036 + 320166037.

It is an arithmetic number, because the mean of its divisors is an integer number (320166037).

Almost surely, 2^640332073 is an apocalyptic number.

It is an amenable number.

640332073 is a deficient number, since it is larger than the sum of its proper divisors (1).

640332073 is an equidigital number, since it uses as much as digits as its factorization.

640332073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 28.

The square root of 640332073 is about 25304.7835991537. The cubic root of 640332073 is about 861.9228980731.

The spelling of 640332073 in words is "six hundred forty million, three hundred thirty-two thousand, seventy-three".