1981439069 has 2 divisors, whose sum is σ = 1981439070. Its totient is φ = 1981439068.

The previous prime is 1981439041. The next prime is 1981439077. The reversal of 1981439069 is 9609341891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1454507044 + 526932025 = 38138^2 + 22955^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981439069 - 2⁸ = 1981438813 is a prime.

It is a super-3 number, since 3×1981439069³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981439869) 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, 990719534 + 990719535.

It is an arithmetic number, because the mean of its divisors is an integer number (990719535).

Almost surely, 2^1981439069 is an apocalyptic number.

It is an amenable number.

1981439069 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981439069 is an equidigital number, since it uses as much as digits as its factorization.

1981439069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 1981439069 is about 44513.3583208457. The cubic root of 1981439069 is about 1256.0113790350.

The spelling of 1981439069 in words is "one billion, nine hundred eighty-one million, four hundred thirty-nine thousand, sixty-nine".