81723392 has 68 divisors (see below), whose sum is σ = 173013720. Its totient is φ = 38535168.

The previous prime is 81723359. The next prime is 81723401. The reversal of 81723392 is 29332718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1900523 + ... + 1900565.

Almost surely, 2^81723392 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 81723392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86506860).

81723392 is an abundant number, since it is smaller than the sum of its proper divisors (91290328).

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

81723392 is an frugal number, since it uses more digits than its factorization.

81723392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104 (or 74 counting only the distinct ones).

The product of its digits is 18144, while the sum is 35.

The square root of 81723392 is about 9040.0991145009. The cubic root of 81723392 is about 433.9590948727.

The spelling of 81723392 in words is "eighty-one million, seven hundred twenty-three thousand, three hundred ninety-two".