664918385 has 16 divisors (see below), whose sum is σ = 845030016. Its totient is φ = 501207168.

The previous prime is 664918381. The next prime is 664918439. The reversal of 664918385 is 583819466.

It is not a de Polignac number, because 664918385 - 2² = 664918381 is a prime.

It is a super-2 number, since 2×664918385² = 884232917422016450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664918381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35444 + ... + 50853.

It is an arithmetic number, because the mean of its divisors is an integer number (52814376).

Almost surely, 2^664918385 is an apocalyptic number.

It is an amenable number.

664918385 is a deficient number, since it is larger than the sum of its proper divisors (180111631).

664918385 is a wasteful number, since it uses less digits than its factorization.

664918385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86392.

The product of its digits is 1244160, while the sum is 50.

The square root of 664918385 is about 25786.0114209236. The cubic root of 664918385 is about 872.8161638844.

The spelling of 664918385 in words is "six hundred sixty-four million, nine hundred eighteen thousand, three hundred eighty-five".