81285404 has 12 divisors (see below), whose sum is σ = 148434384. Its totient is φ = 38875584.

The previous prime is 81285403. The next prime is 81285409. The reversal of 81285404 is 40458218.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81285403) 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, 441677 + ... + 441860.

It is an arithmetic number, because the mean of its divisors is an integer number (12369532).

Almost surely, 2^81285404 is an apocalyptic number.

It is an amenable number.

81285404 is a deficient number, since it is larger than the sum of its proper divisors (67148980).

81285404 is a wasteful number, since it uses less digits than its factorization.

81285404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883564 (or 883562 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 32.

The square root of 81285404 is about 9015.8418353474. The cubic root of 81285404 is about 433.1824529287.

The spelling of 81285404 in words is "eighty-one million, two hundred eighty-five thousand, four hundred four".