81194690304 has 756 divisors, whose sum is σ = 304859726136. Its totient is φ = 21382631424.

The previous prime is 81194690257. The next prime is 81194690501. The reversal of 81194690304 is 40309649118.

It is a tau number, because it is divible by the number of its divisors (756).

It is a super-2 number, since 2×81194690304² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81194690304.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 118879147 + ... + 118879829.

It is an arithmetic number, because the mean of its divisors is an integer number (403253606).

Almost surely, 2^81194690304 is an apocalyptic number.

81194690304 is a gapful number since it is divisible by the number (84) 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 81194690304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152429863068).

81194690304 is an abundant number, since it is smaller than the sum of its proper divisors (223665035832).

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

81194690304 is an equidigital number, since it uses as much as digits as its factorization.

81194690304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 81194690304 in words is "eighty-one billion, one hundred ninety-four million, six hundred ninety thousand, three hundred four".