81923824 has 40 divisors (see below), whose sum is σ = 164672000. Its totient is φ = 39441600.

The previous prime is 81923791. The next prime is 81923837. The reversal of 81923824 is 42832918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163927 + ... + 164425.

It is an arithmetic number, because the mean of its divisors is an integer number (4116800).

Almost surely, 2^81923824 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 81923824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82336000).

81923824 is an abundant number, since it is smaller than the sum of its proper divisors (82748176).

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

81923824 is a wasteful number, since it uses less digits than its factorization.

81923824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869 (or 863 counting only the distinct ones).

The product of its digits is 27648, while the sum is 37.

The square root of 81923824 is about 9051.1780448735. The cubic root of 81923824 is about 434.3135763189.

The spelling of 81923824 in words is "eighty-one million, nine hundred twenty-three thousand, eight hundred twenty-four".