1966989181 has 2 divisors, whose sum is σ = 1966989182. Its totient is φ = 1966989180.

The previous prime is 1966989137. The next prime is 1966989191. The reversal of 1966989181 is 1819896691.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1966124281 + 864900 = 44341^2 + 930^2 .

It is an emirp because it is prime and its reverse (1819896691) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1816869961 and 1699686181.

It is a cyclic number.

It is not a de Polignac number, because 1966989181 - 2¹¹ = 1966987133 is a prime.

It is a super-2 number, since 2×1966989181² = 7738092876342101522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1966989191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983494590 + 983494591.

It is an arithmetic number, because the mean of its divisors is an integer number (983494591).

Almost surely, 2^1966989181 is an apocalyptic number.

It is an amenable number.

1966989181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966989181 is an equidigital number, since it uses as much as digits as its factorization.

1966989181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1679616, while the sum is 58.

The square root of 1966989181 is about 44350.7517523660. The cubic root of 1966989181 is about 1252.9507210620.

The spelling of 1966989181 in words is "one billion, nine hundred sixty-six million, nine hundred eighty-nine thousand, one hundred eighty-one".