1981442997 has 6 divisors (see below), whose sum is σ = 2862084342. Its totient is φ = 1320961992.

The previous prime is 1981442993. The next prime is 1981443017. The reversal of 1981442997 is 7992441891.

1981442997 is a `hidden beast` number, since 198 + 1 + 442 + 9 + 9 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1708499556 + 272943441 = 41334^2 + 16521^2 .

It is not a de Polignac number, because 1981442997 - 2² = 1981442993 is a prime.

It is a super-3 number, since 3×1981442997³ (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 an unprimeable number, because it can be changed into a prime (1981442993) 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, 110080158 + ... + 110080175.

It is an arithmetic number, because the mean of its divisors is an integer number (477014057).

Almost surely, 2^1981442997 is an apocalyptic number.

It is an amenable number.

1981442997 is a deficient number, since it is larger than the sum of its proper divisors (880641345).

1981442997 is a wasteful number, since it uses less digits than its factorization.

1981442997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220160339 (or 220160336 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 1981442997 is about 44513.4024424105. The cubic root of 1981442997 is about 1256.0122090058.

The spelling of 1981442997 in words is "one billion, nine hundred eighty-one million, four hundred forty-two thousand, nine hundred ninety-seven".