664838825881 has 8 divisors (see below), whose sum is σ = 665626505544. Its totient is φ = 664051407360.

The previous prime is 664838825867. The next prime is 664838825957. The reversal of 664838825881 is 188528838466.

It can be written as a sum of positive squares in 4 ways, for example, as 51529000000 + 613309825881 = 227000^2 + 783141^2 .

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 664838825881 - 2¹³ = 664838817689 is a prime.

It is a super-2 number, since 2×664838825881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664838825801) 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, 5287515 + ... + 5411791.

It is an arithmetic number, because the mean of its divisors is an integer number (83203313193).

Almost surely, 2^664838825881 is an apocalyptic number.

It is an amenable number.

664838825881 is a deficient number, since it is larger than the sum of its proper divisors (787679663).

664838825881 is a wasteful number, since it uses less digits than its factorization.

664838825881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130571.

The product of its digits is 141557760, while the sum is 67.

The spelling of 664838825881 in words is "six hundred sixty-four billion, eight hundred thirty-eight million, eight hundred twenty-five thousand, eight hundred eighty-one".