81505336 has 32 divisors (see below), whose sum is σ = 168739200. Its totient is φ = 36598240.

The previous prime is 81505313. The next prime is 81505343. The reversal of 81505336 is 63350518.

It is a junction number, because it is equal to n+sod(n) for n = 81505298 and 81505307.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1725 + ... + 12883.

It is an arithmetic number, because the mean of its divisors is an integer number (5273100).

Almost surely, 2^81505336 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 81505336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84369600).

81505336 is an abundant number, since it is smaller than the sum of its proper divisors (87233864).

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

81505336 is a wasteful number, since it uses less digits than its factorization.

81505336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11259 (or 11255 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 81505336 is about 9028.0305715034. The cubic root of 81505336 is about 433.5727849506.

The spelling of 81505336 in words is "eighty-one million, five hundred five thousand, three hundred thirty-six".