640842743 has 2 divisors, whose sum is σ = 640842744. Its totient is φ = 640842742.

The previous prime is 640842737. The next prime is 640842749. The reversal of 640842743 is 347248046.

It is a balanced prime because it is at equal distance from previous prime (640842737) and next prime (640842749).

It is a cyclic number.

It is not a de Polignac number, because 640842743 - 2⁶ = 640842679 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640842697 and 640842706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640842749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320421371 + 320421372.

It is an arithmetic number, because the mean of its divisors is an integer number (320421372).

Almost surely, 2^640842743 is an apocalyptic number.

640842743 is a deficient number, since it is larger than the sum of its proper divisors (1).

640842743 is an equidigital number, since it uses as much as digits as its factorization.

640842743 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129024, while the sum is 38.

The square root of 640842743 is about 25314.8719728147. The cubic root of 640842743 is about 862.1519673466.

The spelling of 640842743 in words is "six hundred forty million, eight hundred forty-two thousand, seven hundred forty-three".