81797396400 has 360 divisors, whose sum is σ = 297949055040. Its totient is φ = 21547710720.

The previous prime is 81797396393. The next prime is 81797396431. The reversal of 81797396400 is 469379718.

It is a happy number.

81797396400 is a `hidden beast` number, since 81 + 7 + 9 + 73 + 96 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

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

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, 8062531 + ... + 8072669.

It is an arithmetic number, because the mean of its divisors is an integer number (827636264).

Almost surely, 2^81797396400 is an apocalyptic number.

81797396400 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 81797396400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148974527520).

81797396400 is an abundant number, since it is smaller than the sum of its proper divisors (216151658640).

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

81797396400 is a wasteful number, since it uses less digits than its factorization.

81797396400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10255 (or 10232 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 54.

The spelling of 81797396400 in words is "eighty-one billion, seven hundred ninety-seven million, three hundred ninety-six thousand, four hundred".