81163274400 has 576 divisors, whose sum is σ = 327054067200. Its totient is φ = 19287797760.

The previous prime is 81163274393. The next prime is 81163274417. The reversal of 81163274400 is 447236118.

81163274400 is a `hidden beast` number, since 8 + 11 + 632 + 7 + 4 + 4 + 0 + 0 = 666.

It is a super-2 number, since 2×81163274400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 8138217 + ... + 8148183.

It is an arithmetic number, because the mean of its divisors is an integer number (567802200).

Almost surely, 2^81163274400 is an apocalyptic number.

81163274400 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 81163274400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163527033600).

81163274400 is an abundant number, since it is smaller than the sum of its proper divisors (245890792800).

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

81163274400 is a wasteful number, since it uses less digits than its factorization.

81163274400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10038 (or 10019 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 81163274400 in words is "eighty-one billion, one hundred sixty-three million, two hundred seventy-four thousand, four hundred".