1943981361 has 36 divisors (see below), whose sum is σ = 3307824000. Its totient is φ = 1096765488.

The previous prime is 1943981359. The next prime is 1943981381. The reversal of 1943981361 is 1631893491.

1943981361 is a `hidden beast` number, since 194 + 398 + 13 + 61 = 666.

It is not a de Polignac number, because 1943981361 - 2¹ = 1943981359 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1943981311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6940 + ... + 62738.

It is an arithmetic number, because the mean of its divisors is an integer number (91884000).

Almost surely, 2^1943981361 is an apocalyptic number.

It is an amenable number.

1943981361 is a deficient number, since it is larger than the sum of its proper divisors (1363842639).

1943981361 is a wasteful number, since it uses less digits than its factorization.

1943981361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55898 (or 55888 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 1943981361 is about 44090.6039990382. The cubic root of 1943981361 is about 1248.0463050651.

The spelling of 1943981361 in words is "one billion, nine hundred forty-three million, nine hundred eighty-one thousand, three hundred sixty-one".