81705204 has 72 divisors (see below), whose sum is σ = 238754880. Its totient is φ = 23075712.

The previous prime is 81705191. The next prime is 81705229. The reversal of 81705204 is 40250718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20607 + ... + 24249.

It is an arithmetic number, because the mean of its divisors is an integer number (3316040).

Almost surely, 2^81705204 is an apocalyptic number.

81705204 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 81705204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119377440).

81705204 is an abundant number, since it is smaller than the sum of its proper divisors (157049676).

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

81705204 is a wasteful number, since it uses less digits than its factorization.

81705204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3749 (or 3744 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 81705204 is about 9039.0930961021. The cubic root of 81705204 is about 433.9268991393.

The spelling of 81705204 in words is "eighty-one million, seven hundred five thousand, two hundred four".