81909528480 has 384 divisors, whose sum is σ = 317088172800. Its totient is φ = 19616919552.

The previous prime is 81909528479. The next prime is 81909528497. The reversal of 81909528480 is 8482590918.

It is a super-2 number, since 2×81909528480² (a number of 23 digits) contains 22 as substring.

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 63 ways as a sum of consecutive naturals, for example, 2058211 + ... + 2097629.

It is an arithmetic number, because the mean of its divisors is an integer number (825750450).

Almost surely, 2^81909528480 is an apocalyptic number.

81909528480 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 81909528480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158544086400).

81909528480 is an abundant number, since it is smaller than the sum of its proper divisors (235178644320).

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

81909528480 is a wasteful number, since it uses less digits than its factorization.

81909528480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39493 (or 39479 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 81909528480 in words is "eighty-one billion, nine hundred nine million, five hundred twenty-eight thousand, four hundred eighty".