81919283880 has 384 divisors, whose sum is σ = 291841678080. Its totient is φ = 18336890880.

The previous prime is 81919283813. The next prime is 81919283909. The reversal of 81919283880 is 8838291918.

It is a self number, because there is not a number n which added to its sum of digits gives 81919283880.

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, 126613717 + ... + 126614363.

It is an arithmetic number, because the mean of its divisors is an integer number (760004370).

Almost surely, 2^81919283880 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81919283880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145920839040).

81919283880 is an abundant number, since it is smaller than the sum of its proper divisors (209922394200).

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

81919283880 is a wasteful number, since it uses less digits than its factorization.

81919283880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089 (or 1078 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 57.

The spelling of 81919283880 in words is "eighty-one billion, nine hundred nineteen million, two hundred eighty-three thousand, eight hundred eighty".