38327721665 has 4 divisors (see below), whose sum is σ = 45993266004. Its totient is φ = 30662177328.

The previous prime is 38327721661. The next prime is 38327721683. The reversal of 38327721665 is 56612772383.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16072154176 + 22255567489 = 126776^2 + 149183^2 .

It is a cyclic number.

It is not a de Polignac number, because 38327721665 - 2² = 38327721661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (38327721661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3832772162 + ... + 3832772171.

It is an arithmetic number, because the mean of its divisors is an integer number (11498316501).

Almost surely, 2^38327721665 is an apocalyptic number.

It is an amenable number.

38327721665 is a deficient number, since it is larger than the sum of its proper divisors (7665544339).

38327721665 is an equidigital number, since it uses as much as digits as its factorization.

38327721665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7665544338.

The product of its digits is 2540160, while the sum is 50.

The spelling of 38327721665 in words is "thirty-eight billion, three hundred twenty-seven million, seven hundred twenty-one thousand, six hundred sixty-five".