1966685984551 has 2 divisors, whose sum is σ = 1966685984552. Its totient is φ = 1966685984550.

The previous prime is 1966685984507. The next prime is 1966685984611. The reversal of 1966685984551 is 1554895866691.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1966685984551 - 2¹⁹ = 1966685460263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1966685984051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983342992275 + 983342992276.

It is an arithmetic number, because the mean of its divisors is an integer number (983342992276).

Almost surely, 2^{1966685984551} is an apocalyptic number.

1966685984551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966685984551 is an equidigital number, since it uses as much as digits as its factorization.

1966685984551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872000, while the sum is 73.

The spelling of 1966685984551 in words is "one trillion, nine hundred sixty-six billion, six hundred eighty-five million, nine hundred eighty-four thousand, five hundred fifty-one".