71985906 has 96 divisors (see below), whose sum is σ = 172523520. Its totient is φ = 21621600.

The previous prime is 71985899. The next prime is 71985911. The reversal of 71985906 is 60958917.

It is a Curzon 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 47 ways as a sum of consecutive naturals, for example, 911175 + ... + 911253.

It is an arithmetic number, because the mean of its divisors is an integer number (1797120).

Almost surely, 2^71985906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71985906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86261760).

71985906 is an abundant number, since it is smaller than the sum of its proper divisors (100537614).

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

71985906 is a wasteful number, since it uses less digits than its factorization.

71985906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 71985906 is about 8484.4508366776. The cubic root of 71985906 is about 415.9896177451.

The spelling of 71985906 in words is "seventy-one million, nine hundred eighty-five thousand, nine hundred six".