1681978941 has 6 divisors (see below), whose sum is σ = 2429525150. Its totient is φ = 1121319288.

The previous prime is 1681978939. The next prime is 1681978943. The reversal of 1681978941 is 1498791861.

It is an interprime number because it is at equal distance from previous prime (1681978939) and next prime (1681978943).

It can be written as a sum of positive squares in only one way, i.e., 1461456441 + 220522500 = 38229^2 + 14850^2 .

It is not a de Polignac number, because 1681978941 - 2¹ = 1681978939 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681978943) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 93443266 + ... + 93443283.

Almost surely, 2^1681978941 is an apocalyptic number.

It is an amenable number.

1681978941 is a deficient number, since it is larger than the sum of its proper divisors (747546209).

1681978941 is a wasteful number, since it uses less digits than its factorization.

1681978941 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186886555 (or 186886552 counting only the distinct ones).

The product of its digits is 870912, while the sum is 54.

The square root of 1681978941 is about 41011.9365672971. The cubic root of 1681978941 is about 1189.2509800485.

The spelling of 1681978941 in words is "one billion, six hundred eighty-one million, nine hundred seventy-eight thousand, nine hundred forty-one".