81391679280 has 320 divisors, whose sum is σ = 301030732800. Its totient is φ = 20139356160.

The previous prime is 81391679251. The next prime is 81391679363. The reversal of 81391679280 is 8297619318.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2591511 + ... + 2622729.

It is an arithmetic number, because the mean of its divisors is an integer number (940721040).

Almost surely, 2^81391679280 is an apocalyptic number.

81391679280 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 81391679280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150515366400).

81391679280 is an abundant number, since it is smaller than the sum of its proper divisors (219639053520).

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

81391679280 is a wasteful number, since it uses less digits than its factorization.

81391679280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31329 (or 31317 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The spelling of 81391679280 in words is "eighty-one billion, three hundred ninety-one million, six hundred seventy-nine thousand, two hundred eighty".