81616898640000 has 320 divisors, whose sum is σ = 270984275274240. Its totient is φ = 21758289408000.

The previous prime is 81616898639953. The next prime is 81616898640001. The reversal of 81616898640000 is 4689861618.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×81616898640000² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81616898640001) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 872833249 + ... + 872926751.

It is an arithmetic number, because the mean of its divisors is an integer number (846825860232).

Almost surely, 2^{81616898640000} is an apocalyptic number.

81616898640000 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 81616898640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135492137637120).

81616898640000 is an abundant number, since it is smaller than the sum of its proper divisors (189367376634240).

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

81616898640000 is an equidigital number, since it uses as much as digits as its factorization.

81616898640000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97177 (or 97150 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 57.

The spelling of 81616898640000 in words is "eighty-one trillion, six hundred sixteen billion, eight hundred ninety-eight million, six hundred forty thousand".