81946 has 4 divisors (see below), whose sum is σ = 122922. Its totient is φ = 40972.

The previous prime is 81943. The next prime is 81953. The reversal of 81946 is 64918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 46225 + 35721 = 215^2 + 189^2 .

It is not an unprimeable number, because it can be changed into a prime (81943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20485 + ... + 20488.

2⁸¹⁹⁴⁶ is an apocalyptic number.

81946 is a deficient number, since it is larger than the sum of its proper divisors (40976).

81946 is a wasteful number, since it uses less digits than its factorization.

81946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40975.

The product of its digits is 1728, while the sum is 28.

The square root of 81946 is about 286.2621176474. The cubic root of 81946 is about 43.4352760968.

Subtracting from 81946 its sum of digits (28), we obtain a palindrome (81918).

The spelling of 81946 in words is "eighty-one thousand, nine hundred forty-six".