81886797720 has 1280 divisors, whose sum is σ = 358439558400. Its totient is φ = 16303472640.

The previous prime is 81886797703. The next prime is 81886797739. The reversal of 81886797720 is 2779768818.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 521571882 + ... + 521572038.

It is an arithmetic number, because the mean of its divisors is an integer number (280030905).

Almost surely, 2^81886797720 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 81886797720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179219779200).

81886797720 is an abundant number, since it is smaller than the sum of its proper divisors (276552760680).

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

81886797720 is a wasteful number, since it uses less digits than its factorization.

81886797720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290 (or 277 counting only the distinct ones).

The product of its (nonzero) digits is 18966528, while the sum is 63.

The spelling of 81886797720 in words is "eighty-one billion, eight hundred eighty-six million, seven hundred ninety-seven thousand, seven hundred twenty".