997327981 has 6 divisors (see below), whose sum is σ = 1079947050. Its totient is φ = 920610288.

The previous prime is 997327973. The next prime is 997327997. The reversal of 997327981 is 189723799.

997327981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 4447881 + 992880100 = 2109^2 + 31510^2 .

It is not a de Polignac number, because 997327981 - 2³ = 997327973 is a prime.

It is a super-5 number, since 5×997327981⁵ (a number of 46 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is the 31581-st Hogben number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997327481) by changing a digit.

It is a nontrivial repunit in base 31580.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2950506 + ... + 2950843.

It is an arithmetic number, because the mean of its divisors is an integer number (179991175).

Almost surely, 2^997327981 is an apocalyptic number.

It is an amenable number.

997327981 is a deficient number, since it is larger than the sum of its proper divisors (82619069).

997327981 is a wasteful number, since it uses less digits than its factorization.

997327981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5901375 (or 5901362 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 55.

The square root of 997327981 is about 31580.5000118744. The cubic root of 997327981 is about 999.1085325219.

The spelling of 997327981 in words is "nine hundred ninety-seven million, three hundred twenty-seven thousand, nine hundred eighty-one".