81644024 has 48 divisors (see below), whose sum is σ = 192318000. Its totient is φ = 31806720.

The previous prime is 81644011. The next prime is 81644033. The reversal of 81644024 is 42044618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 752 + ... + 12800.

It is an arithmetic number, because the mean of its divisors is an integer number (4006625).

Almost surely, 2^81644024 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 81644024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96159000).

81644024 is an abundant number, since it is smaller than the sum of its proper divisors (110673976).

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

81644024 is a wasteful number, since it uses less digits than its factorization.

81644024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12084 (or 12069 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 81644024 is about 9035.7082732899. The cubic root of 81644024 is about 433.8185654578.

The spelling of 81644024 in words is "eighty-one million, six hundred forty-four thousand, twenty-four".