1943938691 has 2 divisors, whose sum is σ = 1943938692. Its totient is φ = 1943938690.

The previous prime is 1943938651. The next prime is 1943938693. The reversal of 1943938691 is 1968393491.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1968393491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1943938691 - 2²⁶ = 1876829827 is a prime.

Together with 1943938693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1943938693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 971969345 + 971969346.

It is an arithmetic number, because the mean of its divisors is an integer number (971969346).

Almost surely, 2^1943938691 is an apocalyptic number.

1943938691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1943938691 is an equidigital number, since it uses as much as digits as its factorization.

1943938691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1259712, while the sum is 53.

The square root of 1943938691 is about 44090.1201064365. The cubic root of 1943938691 is about 1248.0371735431.

The spelling of 1943938691 in words is "one billion, nine hundred forty-three million, nine hundred thirty-eight thousand, six hundred ninety-one".