79981 has 6 divisors (see below), whose sum is σ = 88046. Its totient is φ = 72600.

The previous prime is 79979. The next prime is 79987. The reversal of 79981 is 18997.

79981 is nontrivially palindromic in base 6.

It can be written as a sum of positive squares in only one way, i.e., 75625 + 4356 = 275^2 + 66^2 .

It is not a de Polignac number, because 79981 - 2¹ = 79979 is a prime.

It is a super-2 number, since 2×79981² = 12793920722, which contains 22 as substring.

It is a Duffinian number.

79981 is an undulating number in base 6.

79981 is a lucky number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79987) 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, 210 + ... + 451.

2⁷⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

79981 is a deficient number, since it is larger than the sum of its proper divisors (8065).

79981 is a wasteful number, since it uses less digits than its factorization.

79981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683 (or 672 counting only the distinct ones).

The product of its digits is 4536, while the sum is 34.

The square root of 79981 is about 282.8091229080. The cubic root of 79981 is about 43.0852823423.

The spelling of 79981 in words is "seventy-nine thousand, nine hundred eighty-one".