81960802560 has 2160 divisors, whose sum is σ = 394334374896. Its totient is φ = 16052649984.

The previous prime is 81960802549. The next prime is 81960802589. The reversal of 81960802560 is 6520806918.

81960802560 is a `hidden beast` number, since 8 + 1 + 9 + 6 + 0 + 80 + 2 + 560 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 585252864 + 81375549696 = 24192^2 + 285264^2 .

It is a tau number, because it is divible by the number of its divisors (2160).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 1122750684 + ... + 1122750756.

Almost surely, 2^81960802560 is an apocalyptic number.

81960802560 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 81960802560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197167187448).

81960802560 is an abundant number, since it is smaller than the sum of its proper divisors (312373572336).

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

81960802560 is a wasteful number, since it uses less digits than its factorization.

81960802560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 81960802560 in words is "eighty-one billion, nine hundred sixty million, eight hundred two thousand, five hundred sixty".