664165644 has 12 divisors (see below), whose sum is σ = 1549719864. Its totient is φ = 221388544.

The previous prime is 664165633. The next prime is 664165657. The reversal of 664165644 is 446561466.

664165644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×664165644² = 882232005339869472, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 664165596 and 664165605.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27673557 + ... + 27673580.

It is an arithmetic number, because the mean of its divisors is an integer number (129143322).

Almost surely, 2^664165644 is an apocalyptic number.

It is an amenable number.

664165644 is an abundant number, since it is smaller than the sum of its proper divisors (885554220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664165644 is a wasteful number, since it uses less digits than its factorization.

664165644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55347144 (or 55347142 counting only the distinct ones).

The product of its digits is 414720, while the sum is 42.

The square root of 664165644 is about 25771.4113699658. The cubic root of 664165644 is about 872.4866735238.

The spelling of 664165644 in words is "six hundred sixty-four million, one hundred sixty-five thousand, six hundred forty-four".