664040065 has 16 divisors (see below), whose sum is σ = 860339088. Its totient is φ = 489113856.

The previous prime is 664040011. The next prime is 664040081. The reversal of 664040065 is 560040466.

664040065 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 122500624 + 541539441 = 11068^2 + 23271^2 .

It is a cyclic number.

It is not a de Polignac number, because 664040065 - 2⁹ = 664039553 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12939 + ... + 38671.

It is an arithmetic number, because the mean of its divisors is an integer number (53771193).

Almost surely, 2^664040065 is an apocalyptic number.

664040065 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

664040065 is a deficient number, since it is larger than the sum of its proper divisors (196299023).

664040065 is a wasteful number, since it uses less digits than its factorization.

664040065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26148.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 664040065 is about 25768.9748534939. The cubic root of 664040065 is about 872.4316807615.

The spelling of 664040065 in words is "six hundred sixty-four million, forty thousand, sixty-five".