81623544 has 48 divisors (see below), whose sum is σ = 215386920. Its totient is φ = 25773120.

The previous prime is 81623543. The next prime is 81623557. The reversal of 81623544 is 44532618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81623543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3954 + ... + 13374.

Almost surely, 2^81623544 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 81623544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107693460).

81623544 is an abundant number, since it is smaller than the sum of its proper divisors (133763376).

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

81623544 is a wasteful number, since it uses less digits than its factorization.

81623544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9468 (or 9445 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 81623544 is about 9034.5749208250. The cubic root of 81623544 is about 433.7822886765.

The spelling of 81623544 in words is "eighty-one million, six hundred twenty-three thousand, five hundred forty-four".