640378373 has 2 divisors, whose sum is σ = 640378374. Its totient is φ = 640378372.

The previous prime is 640378363. The next prime is 640378381. The reversal of 640378373 is 373873046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637966564 + 2411809 = 25258^2 + 1553^2 .

It is a cyclic number.

It is not a de Polignac number, because 640378373 - 2¹⁸ = 640116229 is a prime.

It is a super-2 number, since 2×640378373² = 820168921212254258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640378373.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640378313) 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, 320189186 + 320189187.

It is an arithmetic number, because the mean of its divisors is an integer number (320189187).

Almost surely, 2^640378373 is an apocalyptic number.

It is an amenable number.

640378373 is a deficient number, since it is larger than the sum of its proper divisors (1).

640378373 is an equidigital number, since it uses as much as digits as its factorization.

640378373 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 41.

The square root of 640378373 is about 25305.6984294052. The cubic root of 640378373 is about 861.9436717050.

The spelling of 640378373 in words is "six hundred forty million, three hundred seventy-eight thousand, three hundred seventy-three".