381321648666 has 96 divisors (see below), whose sum is σ = 957941157888. Its totient is φ = 107367755040.

The previous prime is 381321648637. The next prime is 381321648667. The reversal of 381321648666 is 666846123183.

It is not an unprimeable number, because it can be changed into a prime (381321648667) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23994175 + ... + 24010061.

It is an arithmetic number, because the mean of its divisors is an integer number (9978553728).

Almost surely, 2^381321648666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 381321648666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (478970578944).

381321648666 is an abundant number, since it is smaller than the sum of its proper divisors (576619509222).

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

381321648666 is a wasteful number, since it uses less digits than its factorization.

381321648666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18656 (or 18653 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 54.

The spelling of 381321648666 in words is "three hundred eighty-one billion, three hundred twenty-one million, six hundred forty-eight thousand, six hundred sixty-six".