664578841861 has 8 divisors (see below), whose sum is σ = 725732645184. Its totient is φ = 603547962720.

The previous prime is 664578841807. The next prime is 664578841919. The reversal of 664578841861 is 168148875466.

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

It is a cyclic number.

It is not a de Polignac number, because 664578841861 - 2³⁹ = 114823027973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 664578841793 and 664578841802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664578841361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30719736 + ... + 30741361.

It is an arithmetic number, because the mean of its divisors is an integer number (90716580648).

Almost surely, 2^664578841861 is an apocalyptic number.

It is an amenable number.

664578841861 is a deficient number, since it is larger than the sum of its proper divisors (61153803323).

664578841861 is a wasteful number, since it uses less digits than its factorization.

664578841861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61462091.

The product of its digits is 61931520, while the sum is 64.

The spelling of 664578841861 in words is "six hundred sixty-four billion, five hundred seventy-eight million, eight hundred forty-one thousand, eight hundred sixty-one".