640215781307 has 2 divisors, whose sum is σ = 640215781308. Its totient is φ = 640215781306.

The previous prime is 640215781237. The next prime is 640215781357. The reversal of 640215781307 is 703187512046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640215781307 - 2³⁰ = 639142039483 is a prime.

It is not a weakly prime, because it can be changed into another prime (640215781357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320107890653 + 320107890654.

It is an arithmetic number, because the mean of its divisors is an integer number (320107890654).

Almost surely, 2^640215781307 is an apocalyptic number.

640215781307 is a deficient number, since it is larger than the sum of its proper divisors (1).

640215781307 is an equidigital number, since it uses as much as digits as its factorization.

640215781307 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 640215781307 in words is "six hundred forty billion, two hundred fifteen million, seven hundred eighty-one thousand, three hundred seven".