81869760 has 336 divisors, whose sum is σ = 334743552. Its totient is φ = 17971200.

The previous prime is 81869741. The next prime is 81869761. The reversal of 81869760 is 6796818.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81869761) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 624895 + ... + 625025.

Almost surely, 2^81869760 is an apocalyptic number.

81869760 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 81869760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (167371776).

81869760 is an abundant number, since it is smaller than the sum of its proper divisors (252873792).

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

81869760 is a wasteful number, since it uses less digits than its factorization.

81869760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 81869760 is about 9048.1909794168. The cubic root of 81869760 is about 434.2180164229.

The spelling of 81869760 in words is "eighty-one million, eight hundred sixty-nine thousand, seven hundred sixty".