81404 has 12 divisors (see below), whose sum is σ = 145824. Its totient is φ = 39744.

The previous prime is 81401. The next prime is 81409. The reversal of 81404 is 40418.

It is a happy number.

It is a super-2 number, since 2×81404² = 13253222432, which contains 22 as substring.

It is a plaindrome in base 9.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81404.

It is not an unprimeable number, because it can be changed into a prime (81401) 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, 29 + ... + 404.

It is an arithmetic number, because the mean of its divisors is an integer number (12152).

2⁸¹⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

81404 is a deficient number, since it is larger than the sum of its proper divisors (64420).

81404 is a wasteful number, since it uses less digits than its factorization.

81404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 484 (or 482 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 81404 is about 285.3138622640. The cubic root of 81404 is about 43.3393022678.

The spelling of 81404 in words is "eighty-one thousand, four hundred four".