81323724 has 48 divisors (see below), whose sum is σ = 204019200. Its totient is φ = 25131456.

The previous prime is 81323719. The next prime is 81323741. The reversal of 81323724 is 42732318.

It is a super-2 number, since 2×81323724² = 13227096170456352, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81323691 and 81323700.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6922 + ... + 14510.

It is an arithmetic number, because the mean of its divisors is an integer number (4250400).

Almost surely, 2^81323724 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 81323724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102009600).

81323724 is an abundant number, since it is smaller than the sum of its proper divisors (122695476).

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

81323724 is a wasteful number, since it uses less digits than its factorization.

81323724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7662 (or 7660 counting only the distinct ones).

The product of its digits is 8064, while the sum is 30.

The square root of 81323724 is about 9017.9667331389. The cubic root of 81323724 is about 433.2505132978.

The spelling of 81323724 in words is "eighty-one million, three hundred twenty-three thousand, seven hundred twenty-four".