1966236781 has 2 divisors, whose sum is σ = 1966236782. Its totient is φ = 1966236780.

The previous prime is 1966236763. The next prime is 1966236799. The reversal of 1966236781 is 1876326691.

It is a balanced prime because it is at equal distance from previous prime (1966236763) and next prime (1966236799).

It can be written as a sum of positive squares in only one way, i.e., 1809736681 + 156500100 = 42541^2 + 12510^2 .

It is an emirp because it is prime and its reverse (1876326691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1966236781 - 2¹¹ = 1966234733 is a prime.

It is a super-2 number, since 2×1966236781² = 7732174157914483922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1966236281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983118390 + 983118391.

It is an arithmetic number, because the mean of its divisors is an integer number (983118391).

Almost surely, 2^1966236781 is an apocalyptic number.

It is an amenable number.

1966236781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966236781 is an equidigital number, since it uses as much as digits as its factorization.

1966236781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 49.

The square root of 1966236781 is about 44342.2685594682. The cubic root of 1966236781 is about 1252.7909438150.

The spelling of 1966236781 in words is "one billion, nine hundred sixty-six million, two hundred thirty-six thousand, seven hundred eighty-one".