81613056 has 288 divisors, whose sum is σ = 282562560. Its totient is φ = 20348928.

The previous prime is 81613033. The next prime is 81613061. The reversal of 81613056 is 65031618.

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, 1736425 + ... + 1736471.

It is an arithmetic number, because the mean of its divisors is an integer number (981120).

Almost surely, 2^81613056 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 81613056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141281280).

81613056 is an abundant number, since it is smaller than the sum of its proper divisors (200949504).

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

81613056 is a wasteful number, since it uses less digits than its factorization.

81613056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 81613056 is about 9033.9944653514. The cubic root of 81613056 is about 433.7637086472.

It can be divided in two parts, 816 and 13056, that multiplied together give a square (10653696 = 3264²).

The spelling of 81613056 in words is "eighty-one million, six hundred thirteen thousand, fifty-six".