81923328 has 162 divisors, whose sum is σ = 250666962. Its totient is φ = 25712640.

The previous prime is 81923327. The next prime is 81923333. The reversal of 81923328 is 82332918.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 79709184 + 2214144 = 8928^2 + 1488^2 .

It is a super-2 number, since 2×81923328² = 13422863341191168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 81923292 and 81923301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81923327) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2214126 + ... + 2214162.

Almost surely, 2^81923328 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 81923328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125333481).

81923328 is an abundant number, since it is smaller than the sum of its proper divisors (168743634).

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

81923328 is a wasteful number, since it uses less digits than its factorization.

81923328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 73 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 81923328 is about 9051.1506450838. The cubic root of 81923328 is about 434.3126998137.

The spelling of 81923328 in words is "eighty-one million, nine hundred twenty-three thousand, three hundred twenty-eight".