81554688 has 252 divisors, whose sum is σ = 268091040. Its totient is φ = 24634368.

The previous prime is 81554677. The next prime is 81554689. The reversal of 81554688 is 88645518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81554689) by changing a digit.

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 27 ways as a sum of consecutive naturals, for example, 3545845 + ... + 3545867.

Almost surely, 2^81554688 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 81554688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134045520).

81554688 is an abundant number, since it is smaller than the sum of its proper divisors (186536352).

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

81554688 is an equidigital number, since it uses as much as digits as its factorization.

81554688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76 (or 47 counting only the distinct ones).

The product of its digits is 307200, while the sum is 45.

The square root of 81554688 is about 9030.7634228785. The cubic root of 81554688 is about 433.6602776546.

The spelling of 81554688 in words is "eighty-one million, five hundred fifty-four thousand, six hundred eighty-eight".