640016987 has 2 divisors, whose sum is σ = 640016988. Its totient is φ = 640016986.

The previous prime is 640016983. The next prime is 640017013. The reversal of 640016987 is 789610046.

640016987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640016987 - 2² = 640016983 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640016983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320008493 + 320008494.

It is an arithmetic number, because the mean of its divisors is an integer number (320008494).

Almost surely, 2^640016987 is an apocalyptic number.

640016987 is a deficient number, since it is larger than the sum of its proper divisors (1).

640016987 is an equidigital number, since it uses as much as digits as its factorization.

640016987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 640016987 is about 25298.5570141856. The cubic root of 640016987 is about 861.7815003999.

The spelling of 640016987 in words is "six hundred forty million, sixteen thousand, nine hundred eighty-seven".