73981 has 4 divisors (see below), whose sum is σ = 74592. Its totient is φ = 73372.

The previous prime is 73973. The next prime is 73999. The reversal of 73981 is 18937.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18937 = 29 ⋅653.

It is a cyclic number.

It is not a de Polignac number, because 73981 - 2³ = 73973 is a prime.

It is a super-2 number, since 2×73981² = 10946376722, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55 + ... + 388.

It is an arithmetic number, because the mean of its divisors is an integer number (18648).

2⁷³⁹⁸¹ is an apocalyptic number.

It is an amenable number.

73981 is a deficient number, since it is larger than the sum of its proper divisors (611).

73981 is a wasteful number, since it uses less digits than its factorization.

73981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610.

The product of its digits is 1512, while the sum is 28.

The square root of 73981 is about 271.9944852382. The cubic root of 73981 is about 41.9797710597.

It can be divided in two parts, 739 and 81, that added together give a triangular number (820 = T₄₀).

The spelling of 73981 in words is "seventy-three thousand, nine hundred eighty-one".