664683681 has 8 divisors (see below), whose sum is σ = 890699200. Its totient is φ = 440895312.

The previous prime is 664683661. The next prime is 664683749. The reversal of 664683681 is 186386466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 664683681 - 2²⁵ = 631129249 is a prime.

It is a super-3 number, since 3×664683681³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664683681.

It is not an unprimeable number, because it can be changed into a prime (664683661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 556090 + ... + 557283.

It is an arithmetic number, because the mean of its divisors is an integer number (111337400).

Almost surely, 2^664683681 is an apocalyptic number.

It is an amenable number.

664683681 is a deficient number, since it is larger than the sum of its proper divisors (226015519).

664683681 is a wasteful number, since it uses less digits than its factorization.

664683681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1113575.

The product of its digits is 995328, while the sum is 48.

The square root of 664683681 is about 25781.4600245991. The cubic root of 664683681 is about 872.7134557639.

The spelling of 664683681 in words is "six hundred sixty-four million, six hundred eighty-three thousand, six hundred eighty-one".