664069987 has 16 divisors (see below), whose sum is σ = 765998080. Its totient is φ = 563931072.

The previous prime is 664069981. The next prime is 664069999. The reversal of 664069987 is 789960466.

It is a cyclic number.

It is not a de Polignac number, because 664069987 - 2³ = 664069979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664069981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 465958 + ... + 467380.

It is an arithmetic number, because the mean of its divisors is an integer number (47874880).

Almost surely, 2^664069987 is an apocalyptic number.

664069987 is a deficient number, since it is larger than the sum of its proper divisors (101928093).

664069987 is a wasteful number, since it uses less digits than its factorization.

664069987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2002.

The product of its (nonzero) digits is 3919104, while the sum is 55.

The square root of 664069987 is about 25769.5554288389. Note that the first 3 decimals coincide. The cubic root of 664069987 is about 872.4447846438. Note that the first 3 decimals are identical.

The spelling of 664069987 in words is "six hundred sixty-four million, sixty-nine thousand, nine hundred eighty-seven".