81406 has 16 divisors (see below), whose sum is σ = 137088. Its totient is φ = 36000.

The previous prime is 81401. The next prime is 81409. The reversal of 81406 is 60418.

81406 is a nontrivial binomial coefficient, being equal to C(404, 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401) by changing a digit.

81406 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 756 + ... + 856.

It is an arithmetic number, because the mean of its divisors is an integer number (8568).

2⁸¹⁴⁰⁶ is an apocalyptic number.

81406 is the 403-rd triangular number and also the 202-nd hexagonal number.

81406 is the 135-th centered nonagonal number.

81406 is a deficient number, since it is larger than the sum of its proper divisors (55682).

81406 is a wasteful number, since it uses less digits than its factorization.

81406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 81406 is about 285.3173671545. The cubic root of 81406 is about 43.3396571967.

The spelling of 81406 in words is "eighty-one thousand, four hundred six".