81393500 has 24 divisors (see below), whose sum is σ = 177764496. Its totient is φ = 32557200.

The previous prime is 81393457. The next prime is 81393523. The reversal of 81393500 is 539318.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80894 + ... + 81893.

It is an arithmetic number, because the mean of its divisors is an integer number (7406854).

Almost surely, 2^81393500 is an apocalyptic number.

It is an amenable number.

81393500 is an abundant number, since it is smaller than the sum of its proper divisors (96370996).

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

81393500 is a wasteful number, since it uses less digits than its factorization.

81393500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162806 (or 162794 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 81393500 is about 9021.8346249530. The cubic root of 81393500 is about 433.3743879578.

The spelling of 81393500 in words is "eighty-one million, three hundred ninety-three thousand, five hundred".