664671804 has 12 divisors (see below), whose sum is σ = 1550900904. Its totient is φ = 221557264.

The previous prime is 664671739. The next prime is 664671817. The reversal of 664671804 is 408176466.

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

It is a super-2 number, since 2×664671804² = 883577214065228832, which contains 22 as substring.

It is a congruent number.

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, 27694647 + ... + 27694670.

It is an arithmetic number, because the mean of its divisors is an integer number (129241742).

Almost surely, 2^664671804 is an apocalyptic number.

It is an amenable number.

664671804 is an abundant number, since it is smaller than the sum of its proper divisors (886229100).

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

664671804 is a wasteful number, since it uses less digits than its factorization.

664671804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55389324 (or 55389322 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 42.

The square root of 664671804 is about 25781.2296836284. The cubic root of 664671804 is about 872.7082576626.

The spelling of 664671804 in words is "six hundred sixty-four million, six hundred seventy-one thousand, eight hundred four".