64664081 has 4 divisors (see below), whose sum is σ = 65884212. Its totient is φ = 63443952.

The previous prime is 64664029. The next prime is 64664099. The reversal of 64664081 is 18046646.

64664081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18046646 = 2 ⋅9023323.

It can be written as a sum of positive squares in 2 ways, for example, as 46036225 + 18627856 = 6785^2 + 4316^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64664081 is a prime.

It is a super-2 number, since 2×64664081² = 8362886743149122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64664021) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 609986 + ... + 610091.

It is an arithmetic number, because the mean of its divisors is an integer number (16471053).

Almost surely, 2^64664081 is an apocalyptic number.

It is an amenable number.

64664081 is a deficient number, since it is larger than the sum of its proper divisors (1220131).

64664081 is a wasteful number, since it uses less digits than its factorization.

64664081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1220130.

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 64664081 is about 8041.3979506054. The cubic root of 64664081 is about 401.3787442836.

The spelling of 64664081 in words is "sixty-four million, six hundred sixty-four thousand, eighty-one".