81869280 has 192 divisors, whose sum is σ = 278691840. Its totient is φ = 20127744.

The previous prime is 81869273. The next prime is 81869311. The reversal of 81869280 is 8296818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 644577 + ... + 644703.

It is an arithmetic number, because the mean of its divisors is an integer number (1451520).

Almost surely, 2^81869280 is an apocalyptic number.

81869280 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 81869280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139345920).

81869280 is an abundant number, since it is smaller than the sum of its proper divisors (196822560).

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

81869280 is a wasteful number, since it uses less digits than its factorization.

81869280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 81869280 is about 9048.1644547389. The cubic root of 81869280 is about 434.2171678188.

The spelling of 81869280 in words is "eighty-one million, eight hundred sixty-nine thousand, two hundred eighty".