81778132800 has 1008 divisors, whose sum is σ = 378880250112. Its totient is φ = 16234905600.

The previous prime is 81778132789. The next prime is 81778132801. The reversal of 81778132800 is 823187718.

It is a tau number, because it is divible by the number of its divisors (1008).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81778132801) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 22274965 + ... + 22278635.

It is an arithmetic number, because the mean of its divisors is an integer number (375873264).

Almost surely, 2^81778132800 is an apocalyptic number.

81778132800 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 81778132800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189440125056).

81778132800 is an abundant number, since it is smaller than the sum of its proper divisors (297102117312).

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

81778132800 is a wasteful number, since it uses less digits than its factorization.

81778132800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3736 (or 3718 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 45.

The spelling of 81778132800 in words is "eighty-one billion, seven hundred seventy-eight million, one hundred thirty-two thousand, eight hundred".