640057787 has 2 divisors, whose sum is σ = 640057788. Its totient is φ = 640057786.

The previous prime is 640057751. The next prime is 640057813. The reversal of 640057787 is 787750046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640057787 - 2⁶ = 640057723 is a prime.

It is not a weakly prime, because it can be changed into another prime (640057387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320028893 + 320028894.

It is an arithmetic number, because the mean of its divisors is an integer number (320028894).

Almost surely, 2^640057787 is an apocalyptic number.

640057787 is a deficient number, since it is larger than the sum of its proper divisors (1).

640057787 is an equidigital number, since it uses as much as digits as its factorization.

640057787 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 329280, while the sum is 44.

The square root of 640057787 is about 25299.3633714368. The cubic root of 640057787 is about 861.7998123816.

The spelling of 640057787 in words is "six hundred forty million, fifty-seven thousand, seven hundred eighty-seven".