81193320 has 128 divisors (see below), whose sum is σ = 291513600. Its totient is φ = 19982592.

The previous prime is 81193313. The next prime is 81193349. The reversal of 81193320 is 2339118.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11149 + ... + 16931.

It is an arithmetic number, because the mean of its divisors is an integer number (2277450).

Almost surely, 2^81193320 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 81193320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145756800).

81193320 is an abundant number, since it is smaller than the sum of its proper divisors (210320280).

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

81193320 is a wasteful number, since it uses less digits than its factorization.

81193320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5816 (or 5806 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 81193320 is about 9010.7335994357. The cubic root of 81193320 is about 433.0188145085.

The spelling of 81193320 in words is "eighty-one million, one hundred ninety-three thousand, three hundred twenty".