81489408 has 320 divisors, whose sum is σ = 296980992. Its totient is φ = 19169280.

The previous prime is 81489403. The next prime is 81489431. The reversal of 81489408 is 80498418.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 81489408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81489403) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1537510 + ... + 1537562.

Almost surely, 2^81489408 is an apocalyptic number.

81489408 is a gapful number since it is divisible by the number (88) 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 81489408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148490496).

81489408 is an abundant number, since it is smaller than the sum of its proper divisors (215491584).

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

81489408 is a wasteful number, since it uses less digits than its factorization.

81489408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 42.

The square root of 81489408 is about 9027.1483869492. The cubic root of 81489408 is about 433.5445397764.

The spelling of 81489408 in words is "eighty-one million, four hundred eighty-nine thousand, four hundred eight".