81807760 has 40 divisors (see below), whose sum is σ = 196344576. Its totient is φ = 31666560.

The previous prime is 81807709. The next prime is 81807767. The reversal of 81807760 is 6770818.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (81807767) 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, 14014 + ... + 18973.

Almost surely, 2^81807760 is an apocalyptic number.

81807760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81807760 is an abundant number, since it is smaller than the sum of its proper divisors (114536816).

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

81807760 is a wasteful number, since it uses less digits than its factorization.

81807760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33031 (or 33025 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 37.

The square root of 81807760 is about 9044.7642313108. The cubic root of 81807760 is about 434.1083775861.

The spelling of 81807760 in words is "eighty-one million, eight hundred seven thousand, seven hundred sixty".