16004121643781 has 2 divisors, whose sum is σ = 16004121643782. Its totient is φ = 16004121643780.

The previous prime is 16004121643771. The next prime is 16004121643799. The reversal of 16004121643781 is 18734612140061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10940118532225 + 5064003111556 = 3307585^2 + 2250334^2 .

It is an emirp because it is prime and its reverse (18734612140061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16004121643781 - 2³⁴ = 15986941774597 is a prime.

It is a super-2 number, since 2×16004121643781² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16004121643721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8002060821890 + 8002060821891.

It is an arithmetic number, because the mean of its divisors is an integer number (8002060821891).

Almost surely, 2^{16004121643781} is an apocalyptic number.

It is an amenable number.

16004121643781 is a deficient number, since it is larger than the sum of its proper divisors (1).

16004121643781 is an equidigital number, since it uses as much as digits as its factorization.

16004121643781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 44.

The spelling of 16004121643781 in words is "sixteen trillion, four billion, one hundred twenty-one million, six hundred forty-three thousand, seven hundred eighty-one".