664899861 has 8 divisors (see below), whose sum is σ = 891127360. Its totient is φ = 440969472.

The previous prime is 664899853. The next prime is 664899871. The reversal of 664899861 is 168998466.

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

It is not a de Polignac number, because 664899861 - 2³ = 664899853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664899871) 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 7 ways as a sum of consecutive naturals, for example, 573601 + ... + 574758.

It is an arithmetic number, because the mean of its divisors is an integer number (111390920).

Almost surely, 2^664899861 is an apocalyptic number.

It is an amenable number.

664899861 is a deficient number, since it is larger than the sum of its proper divisors (226227499).

664899861 is a wasteful number, since it uses less digits than its factorization.

664899861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148555.

The product of its digits is 4478976, while the sum is 57.

The square root of 664899861 is about 25785.6522314251. The cubic root of 664899861 is about 872.8080585304.

The spelling of 664899861 in words is "six hundred sixty-four million, eight hundred ninety-nine thousand, eight hundred sixty-one".