664071765 has 48 divisors (see below), whose sum is σ = 1308716352. Its totient is φ = 285712896.

The previous prime is 664071763. The next prime is 664071787. The reversal of 664071765 is 567170466.

It is not a de Polignac number, because 664071765 - 2¹ = 664071763 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664071761) 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 47 ways as a sum of consecutive naturals, for example, 14079 + ... + 39068.

It is an arithmetic number, because the mean of its divisors is an integer number (27264924).

Almost surely, 2^664071765 is an apocalyptic number.

It is an amenable number.

664071765 is a deficient number, since it is larger than the sum of its proper divisors (644644587).

664071765 is a wasteful number, since it uses less digits than its factorization.

664071765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53186 (or 53179 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 42.

The square root of 664071765 is about 25769.5899268886. The cubic root of 664071765 is about 872.4455632794.

The spelling of 664071765 in words is "six hundred sixty-four million, seventy-one thousand, seven hundred sixty-five".