71686640 has 40 divisors (see below), whose sum is σ = 167228880. Its totient is φ = 28578816.

The previous prime is 71686631. The next prime is 71686673. The reversal of 71686640 is 4668617.

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

It is a junction number, because it is equal to n+sod(n) for n = 71686594 and 71686603.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25631 + ... + 28289.

It is an arithmetic number, because the mean of its divisors is an integer number (4180722).

Almost surely, 2^71686640 is an apocalyptic number.

It is an amenable number.

71686640 is an abundant number, since it is smaller than the sum of its proper divisors (95542240).

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

71686640 is a wasteful number, since it uses less digits than its factorization.

71686640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3009 (or 3003 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 71686640 is about 8466.7963244665. The cubic root of 71686640 is about 415.4123544488.

The spelling of 71686640 in words is "seventy-one million, six hundred eighty-six thousand, six hundred forty".