81001036800 has 792 divisors, whose sum is σ = 311827698000. Its totient is φ = 20808990720.

The previous prime is 81001036751. The next prime is 81001036813. The reversal of 81001036800 is 863010018.

It is a super-2 number, since 2×81001036800² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 180402976 + ... + 180403424.

Almost surely, 2^81001036800 is an apocalyptic number.

81001036800 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 81001036800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155913849000).

81001036800 is an abundant number, since it is smaller than the sum of its proper divisors (230826661200).

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

81001036800 is a wasteful number, since it uses less digits than its factorization.

81001036800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

Adding to 81001036800 its reverse (863010018), we get a palindrome (81864046818).

The spelling of 81001036800 in words is "eighty-one billion, one million, thirty-six thousand, eight hundred".