81690556284720 has 240 divisors, whose sum is σ = 282194368672320. Its totient is φ = 21162623625216.

The previous prime is 81690556284691. The next prime is 81690556284761. The reversal of 81690556284720 is 2748265509618.

81690556284720 is a `hidden beast` number, since 8 + 1 + 6 + 9 + 0 + 5 + 562 + 8 + 47 + 20 = 666.

81690556284720 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×81690556284720² (a number of 29 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14866326 + ... + 19605834.

It is an arithmetic number, because the mean of its divisors is an integer number (1175809869468).

Almost surely, 2^{81690556284720} is an apocalyptic number.

81690556284720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81690556284720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141097184336160).

81690556284720 is an abundant number, since it is smaller than the sum of its proper divisors (200503812387600).

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

81690556284720 is a wasteful number, since it uses less digits than its factorization.

81690556284720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4740212 (or 4740203 counting only the distinct ones).

The product of its (nonzero) digits is 58060800, while the sum is 63.

The spelling of 81690556284720 in words is "eighty-one trillion, six hundred ninety billion, five hundred fifty-six million, two hundred eighty-four thousand, seven hundred twenty".