71665550 has 48 divisors (see below), whose sum is σ = 146307600. Its totient is φ = 25900800.

The previous prime is 71665543. The next prime is 71665577. The reversal of 71665550 is 5556617.

It is a self number, because there is not a number n which added to its sum of digits gives 71665550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 125666 + ... + 126234.

It is an arithmetic number, because the mean of its divisors is an integer number (3048075).

Almost surely, 2^71665550 is an apocalyptic number.

71665550 is an abundant number, since it is smaller than the sum of its proper divisors (74642050).

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

71665550 is a wasteful number, since it uses less digits than its factorization.

71665550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 821 (or 816 counting only the distinct ones).

The product of its (nonzero) digits is 31500, while the sum is 35.

The square root of 71665550 is about 8465.5507794827. The cubic root of 71665550 is about 415.3716127529.

It can be divided in two parts, 716 and 65550, that added together give a palindrome (66266).

The spelling of 71665550 in words is "seventy-one million, six hundred sixty-five thousand, five hundred fifty".