81718740 has 96 divisors (see below), whose sum is σ = 260507520. Its totient is φ = 21254400.

The previous prime is 81718673. The next prime is 81718751. The reversal of 81718740 is 4781718.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81718695 and 81718704.

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 31 ways as a sum of consecutive naturals, for example, 20295 + ... + 23985.

It is an arithmetic number, because the mean of its divisors is an integer number (2713620).

Almost surely, 2^81718740 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 81718740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130253760).

81718740 is an abundant number, since it is smaller than the sum of its proper divisors (178788780).

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

81718740 is a wasteful number, since it uses less digits than its factorization.

81718740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3750 (or 3742 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The square root of 81718740 is about 9039.8418127753. The cubic root of 81718740 is about 433.9508605269.

The spelling of 81718740 in words is "eighty-one million, seven hundred eighteen thousand, seven hundred forty".