81445 has 16 divisors (see below), whose sum is σ = 120960. Its totient is φ = 51264.

The previous prime is 81439. The next prime is 81457. The reversal of 81445 is 54418.

It is a cyclic number.

It is not a de Polignac number, because 81445 - 2⁹ = 80933 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366 + ... + 544.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

2⁸¹⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

81445 is a deficient number, since it is larger than the sum of its proper divisors (39515).

81445 is a wasteful number, since it uses less digits than its factorization.

81445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204.

The product of its digits is 640, while the sum is 22.

The square root of 81445 is about 285.3857039166. The cubic root of 81445 is about 43.3465771485.

The spelling of 81445 in words is "eighty-one thousand, four hundred forty-five".