81683320 has 16 divisors (see below), whose sum is σ = 183787560. Its totient is φ = 32673312.

The previous prime is 81683311. The next prime is 81683323. The reversal of 81683320 is 2338618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81683323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1021002 + ... + 1021081.

Almost surely, 2^81683320 is an apocalyptic number.

It is an amenable number.

81683320 is an abundant number, since it is smaller than the sum of its proper divisors (102104240).

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

81683320 is a wasteful number, since it uses less digits than its factorization.

81683320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2042094 (or 2042090 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 81683320 is about 9037.8824953636. The cubic root of 81683320 is about 433.8881545480. Note that the first 3 decimals are identical.

The spelling of 81683320 in words is "eighty-one million, six hundred eighty-three thousand, three hundred twenty".