16661973773981 has 8 divisors (see below), whose sum is σ = 17856310320384. Its totient is φ = 15506795802960.

The previous prime is 16661973773971. The next prime is 16661973774013. The reversal of 16661973773981 is 18937737916661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16661973773981 is a prime.

It is a super-2 number, since 2×16661973773981² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 16661973773899 and 16661973773908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661973773941) 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, 9789642965 + ... + 9789644666.

It is an arithmetic number, because the mean of its divisors is an integer number (2232038790048).

Almost surely, 2^{16661973773981} is an apocalyptic number.

It is an amenable number.

16661973773981 is a deficient number, since it is larger than the sum of its proper divisors (1194336546403).

16661973773981 is a wasteful number, since it uses less digits than its factorization.

16661973773981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19579287691.

The product of its digits is 432081216, while the sum is 74.

The spelling of 16661973773981 in words is "sixteen trillion, six hundred sixty-one billion, nine hundred seventy-three million, seven hundred seventy-three thousand, nine hundred eighty-one".