81604864380 has 288 divisors, whose sum is σ = 270444883968. Its totient is φ = 18294681600.

The previous prime is 81604864379. The next prime is 81604864387. The reversal of 81604864380 is 8346840618.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81604864387) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5336145 + ... + 5351415.

It is an arithmetic number, because the mean of its divisors is an integer number (939044736).

Almost surely, 2^81604864380 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 81604864380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135222441984).

81604864380 is an abundant number, since it is smaller than the sum of its proper divisors (188840019588).

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

81604864380 is a wasteful number, since it uses less digits than its factorization.

81604864380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15357 (or 15342 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 48.

The spelling of 81604864380 in words is "eighty-one billion, six hundred four million, eight hundred sixty-four thousand, three hundred eighty".