640839400067 has 2 divisors, whose sum is σ = 640839400068. Its totient is φ = 640839400066.

The previous prime is 640839400051. The next prime is 640839400129. The reversal of 640839400067 is 760004938046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640839400067 - 2⁴ = 640839400051 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640839399994 and 640839400030.

It is not a weakly prime, because it can be changed into another prime (640839400037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320419700033 + 320419700034.

It is an arithmetic number, because the mean of its divisors is an integer number (320419700034).

Almost surely, 2^640839400067 is an apocalyptic number.

640839400067 is a deficient number, since it is larger than the sum of its proper divisors (1).

640839400067 is an equidigital number, since it uses as much as digits as its factorization.

640839400067 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 47.

The spelling of 640839400067 in words is "six hundred forty billion, eight hundred thirty-nine million, four hundred thousand, sixty-seven".