81628759800 has 384 divisors, whose sum is σ = 331702579200. Its totient is φ = 18055872000.

The previous prime is 81628759777. The next prime is 81628759819. The reversal of 81628759800 is 895782618.

81628759800 is a `hidden beast` number, since 8 + 1 + 628 + 7 + 5 + 9 + 8 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1136970 + ... + 1206630.

It is an arithmetic number, because the mean of its divisors is an integer number (863808800).

Almost surely, 2^81628759800 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 81628759800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165851289600).

81628759800 is an abundant number, since it is smaller than the sum of its proper divisors (250073819400).

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

81628759800 is a wasteful number, since it uses less digits than its factorization.

81628759800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69724 (or 69709 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 54.

The spelling of 81628759800 in words is "eighty-one billion, six hundred twenty-eight million, seven hundred fifty-nine thousand, eight hundred".