81489802240 has 1056 divisors, whose sum is σ = 275997173760. Its totient is φ = 22481141760.

The previous prime is 81489802237. The next prime is 81489802271. The reversal of 81489802240 is 4220898418.

It is a super-2 number, since 2×81489802240² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

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, 1895111659 + ... + 1895111701.

It is an arithmetic number, because the mean of its divisors is an integer number (261360960).

Almost surely, 2^81489802240 is an apocalyptic number.

81489802240 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 81489802240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137998586880).

81489802240 is an abundant number, since it is smaller than the sum of its proper divisors (194507371520).

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

81489802240 is a wasteful number, since it uses less digits than its factorization.

81489802240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 46.

The spelling of 81489802240 in words is "eighty-one billion, four hundred eighty-nine million, eight hundred two thousand, two hundred forty".