81204816 has 160 divisors (see below), whose sum is σ = 265125888. Its totient is φ = 20805120.

The previous prime is 81204797. The next prime is 81204821. The reversal of 81204816 is 61840218.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 469306 + ... + 469478.

Almost surely, 2^81204816 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 81204816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132562944).

81204816 is an abundant number, since it is smaller than the sum of its proper divisors (183921072).

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

81204816 is a wasteful number, since it uses less digits than its factorization.

81204816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329 (or 323 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 81204816 is about 9011.3714827433. The cubic root of 81204816 is about 433.0392503004.

The spelling of 81204816 in words is "eighty-one million, two hundred four thousand, eight hundred sixteen".