81935320 has 32 divisors (see below), whose sum is σ = 185817600. Its totient is φ = 32516064.

The previous prime is 81935311. The next prime is 81935323. The reversal of 81935320 is 2353918.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81935323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 645097 + ... + 645223.

It is an arithmetic number, because the mean of its divisors is an integer number (5806800).

Almost surely, 2^81935320 is an apocalyptic number.

It is an amenable number.

81935320 is an abundant number, since it is smaller than the sum of its proper divisors (103882280).

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

81935320 is an frugal number, since it uses more digits than its factorization.

81935320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 81935320 is about 9051.8130780524. The cubic root of 81935320 is about 434.3338904559. Note that the first 3 decimals are identical.

The spelling of 81935320 in words is "eighty-one million, nine hundred thirty-five thousand, three hundred twenty".