81002905280 has 224 divisors, whose sum is σ = 215897520960. Its totient is φ = 28698624000.

The previous prime is 81002905273. The next prime is 81002905309. The reversal of 81002905280 is 8250920018.

It is a super-2 number, since 2×81002905280² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81002905280.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23402750 + ... + 23406210.

Almost surely, 2^81002905280 is an apocalyptic number.

81002905280 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 81002905280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107948760480).

81002905280 is an abundant number, since it is smaller than the sum of its proper divisors (134894615680).

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

81002905280 is a wasteful number, since it uses less digits than its factorization.

81002905280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3659 (or 3649 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 35.

The spelling of 81002905280 in words is "eighty-one billion, two million, nine hundred five thousand, two hundred eighty".