72981 has 20 divisors (see below), whose sum is σ = 117612. Its totient is φ = 44928.

The previous prime is 72977. The next prime is 72997. The reversal of 72981 is 18927.

It can be written as a sum of positive squares in 2 ways, for example, as 54756 + 18225 = 234^2 + 135^2 .

It is not a de Polignac number, because 72981 - 2² = 72977 is a prime.

It is a super-2 number, since 2×72981² = 10652452722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 72981.

It is not an unprimeable number, because it can be changed into a prime (72901) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1351 + ... + 1403.

2⁷²⁹⁸¹ is an apocalyptic number.

It is an amenable number.

72981 is a deficient number, since it is larger than the sum of its proper divisors (44631).

72981 is a wasteful number, since it uses less digits than its factorization.

72981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 73 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 72981 is about 270.1499583565. The cubic root of 72981 is about 41.7897657385.

It can be divided in two parts, 729 and 81, that multiplied together give a 10-th power (59049 = 3¹⁰).

The spelling of 72981 in words is "seventy-two thousand, nine hundred eighty-one".