81383556 has 72 divisors (see below), whose sum is σ = 208504576. Its totient is φ = 24675840.

The previous prime is 81383543. The next prime is 81383569. The reversal of 81383556 is 65538318.

It is an interprime number because it is at equal distance from previous prime (81383543) and next prime (81383569).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107130 + ... + 107886.

Almost surely, 2^81383556 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 81383556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104252288).

81383556 is an abundant number, since it is smaller than the sum of its proper divisors (127121020).

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

81383556 is a wasteful number, since it uses less digits than its factorization.

81383556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829 (or 810 counting only the distinct ones).

The product of its digits is 86400, while the sum is 39.

The square root of 81383556 is about 9021.2835006999. The cubic root of 81383556 is about 433.3567385123.

The spelling of 81383556 in words is "eighty-one million, three hundred eighty-three thousand, five hundred fifty-six".