81786804 has 144 divisors (see below), whose sum is σ = 228802560. Its totient is φ = 22651200.

The previous prime is 81786799. The next prime is 81786821. The reversal of 81786804 is 40868718.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1035237 + ... + 1035315.

Almost surely, 2^81786804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81786804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114401280).

81786804 is an abundant number, since it is smaller than the sum of its proper divisors (147015756).

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

81786804 is a wasteful number, since it uses less digits than its factorization.

81786804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 42.

The square root of 81786804 is about 9043.6056968446. The cubic root of 81786804 is about 434.0713071336.

It can be divided in two parts, 81 and 786804, that added together give a triangular number (786885 = T₁₂₅₄).

The spelling of 81786804 in words is "eighty-one million, seven hundred eighty-six thousand, eight hundred four".