71644140 has 36 divisors (see below), whose sum is σ = 217321104. Its totient is φ = 19105056.

The previous prime is 71644127. The next prime is 71644141. The reversal of 71644140 is 4144617.

71644140 is a `hidden beast` number, since 7 + 1 + 644 + 14 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (71644141) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 198832 + ... + 199191.

Almost surely, 2^71644140 is an apocalyptic number.

It is an amenable number.

71644140 is an abundant number, since it is smaller than the sum of its proper divisors (145676964).

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

71644140 is a wasteful number, since it uses less digits than its factorization.

71644140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398038 (or 398033 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 71644140 is about 8464.2861482821. The cubic root of 71644140 is about 415.3302447038.

Adding to 71644140 its reverse (4144617), we get a palindrome (75788757).

The spelling of 71644140 in words is "seventy-one million, six hundred forty-four thousand, one hundred forty".