81718480 has 80 divisors (see below), whose sum is σ = 198987264. Its totient is φ = 31173120.

The previous prime is 81718457. The next prime is 81718489. The reversal of 81718480 is 8481718.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81718489) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205642 + ... + 206038.

Almost surely, 2^81718480 is an apocalyptic number.

81718480 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 81718480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99493632).

81718480 is an abundant number, since it is smaller than the sum of its proper divisors (117268784).

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

81718480 is a wasteful number, since it uses less digits than its factorization.

81718480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524 (or 518 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 81718480 is about 9039.8274319812. The cubic root of 81718480 is about 433.9504003006.

The spelling of 81718480 in words is "eighty-one million, seven hundred eighteen thousand, four hundred eighty".