81616186752 has 128 divisors (see below), whose sum is σ = 219823872000. Its totient is φ = 26825969664.

The previous prime is 81616186723. The next prime is 81616186753. The reversal of 81616186752 is 25768161618.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×81616186752² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81616186695 and 81616186704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81616186753) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34248153 + ... + 34250535.

It is an arithmetic number, because the mean of its divisors is an integer number (1717374000).

Almost surely, 2^81616186752 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 81616186752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109911936000).

81616186752 is an abundant number, since it is smaller than the sum of its proper divisors (138207685248).

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

81616186752 is a wasteful number, since it uses less digits than its factorization.

81616186752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3608 (or 3596 counting only the distinct ones).

The product of its digits is 967680, while the sum is 51.

The spelling of 81616186752 in words is "eighty-one billion, six hundred sixteen million, one hundred eighty-six thousand, seven hundred fifty-two".