81743680 has 56 divisors (see below), whose sum is σ = 195425568. Its totient is φ = 32567808.

The previous prime is 81743671. The next prime is 81743687. The reversal of 81743680 is 8634718.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81743687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 149167 + ... + 149713.

Almost surely, 2^81743680 is an apocalyptic number.

81743680 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 81743680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97712784).

81743680 is an abundant number, since it is smaller than the sum of its proper divisors (113681888).

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

81743680 is a wasteful number, since it uses less digits than its factorization.

81743680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031 (or 1021 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 81743680 is about 9041.2211564589. The cubic root of 81743680 is about 433.9950023138.

The spelling of 81743680 in words is "eighty-one million, seven hundred forty-three thousand, six hundred eighty".