89781 has 4 divisors (see below), whose sum is σ = 119712. Its totient is φ = 59852.

The previous prime is 89779. The next prime is 89783. The reversal of 89781 is 18798.

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.

It is an interprime number because it is at equal distance from previous prime (89779) and next prime (89783).

It is a cyclic number.

It is not a de Polignac number, because 89781 - 2¹ = 89779 is a prime.

It is a super-2 number, since 2×89781² = 16121255922, which contains 22 as substring.

It is a D-number.

It is a Curzon number.

89781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (89783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14961 + ... + 14966.

It is an arithmetic number, because the mean of its divisors is an integer number (29928).

2⁸⁹⁷⁸¹ is an apocalyptic number.

It is an amenable number.

89781 is a deficient number, since it is larger than the sum of its proper divisors (29931).

89781 is a wasteful number, since it uses less digits than its factorization.

89781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29930.

The product of its digits is 4032, while the sum is 33.

The square root of 89781 is about 299.6347776878. The cubic root of 89781 is about 44.7776687706. Note that the first 3 decimals are identical.

The spelling of 89781 in words is "eighty-nine thousand, seven hundred eighty-one".