81397835280 has 160 divisors (see below), whose sum is σ = 280478238720. Its totient is φ = 21697735680.

The previous prime is 81397835249. The next prime is 81397835287. The reversal of 81397835280 is 8253879318.

81397835280 is a `hidden beast` number, since 8 + 1 + 39 + 7 + 83 + 528 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (81397835287) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7319004 + ... + 7330116.

It is an arithmetic number, because the mean of its divisors is an integer number (1752988992).

Almost surely, 2^81397835280 is an apocalyptic number.

81397835280 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 81397835280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140239119360).

81397835280 is an abundant number, since it is smaller than the sum of its proper divisors (199080403440).

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

81397835280 is a wasteful number, since it uses less digits than its factorization.

81397835280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14526 (or 14514 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 81397835280 in words is "eighty-one billion, three hundred ninety-seven million, eight hundred thirty-five thousand, two hundred eighty".