640210672691 has 2 divisors, whose sum is σ = 640210672692. Its totient is φ = 640210672690.

The previous prime is 640210672667. The next prime is 640210672711. The reversal of 640210672691 is 196276012046.

640210672691 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 is a cyclic number.

It is not a de Polignac number, because 640210672691 - 2¹⁸ = 640210410547 is a prime.

It is not a weakly prime, because it can be changed into another prime (640210672091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320105336345 + 320105336346.

It is an arithmetic number, because the mean of its divisors is an integer number (320105336346).

Almost surely, 2^640210672691 is an apocalyptic number.

640210672691 is a deficient number, since it is larger than the sum of its proper divisors (1).

640210672691 is an equidigital number, since it uses as much as digits as its factorization.

640210672691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 44.

The spelling of 640210672691 in words is "six hundred forty billion, two hundred ten million, six hundred seventy-two thousand, six hundred ninety-one".