81285204 has 192 divisors, whose sum is σ = 261015552. Its totient is φ = 19008000.

The previous prime is 81285163. The next prime is 81285209. The reversal of 81285204 is 40258218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81285209) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 804754 + ... + 804854.

It is an arithmetic number, because the mean of its divisors is an integer number (1359456).

Almost surely, 2^81285204 is an apocalyptic number.

81285204 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81285204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130507776).

81285204 is an abundant number, since it is smaller than the sum of its proper divisors (179730348).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81285204 is a wasteful number, since it uses less digits than its factorization.

81285204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 81285204 is about 9015.8307437529. The cubic root of 81285204 is about 433.1820976514.

The spelling of 81285204 in words is "eighty-one million, two hundred eighty-five thousand, two hundred four".