71808644 has 6 divisors (see below), whose sum is σ = 125665134. Its totient is φ = 35904320.

The previous prime is 71808643. The next prime is 71808661. The reversal of 71808644 is 44680817.

It can be written as a sum of positive squares in only one way, i.e., 60248644 + 11560000 = 7762^2 + 3400^2 .

It is a junction number, because it is equal to n+sod(n) for n = 71808598 and 71808607.

It is not an unprimeable number, because it can be changed into a prime (71808641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8976077 + ... + 8976084.

It is an arithmetic number, because the mean of its divisors is an integer number (20944189).

Almost surely, 2^71808644 is an apocalyptic number.

It is an amenable number.

71808644 is a deficient number, since it is larger than the sum of its proper divisors (53856490).

71808644 is a wasteful number, since it uses less digits than its factorization.

71808644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17952165 (or 17952163 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 38.

The square root of 71808644 is about 8473.9981118714. The cubic root of 71808644 is about 415.6478852908.

The spelling of 71808644 in words is "seventy-one million, eight hundred eight thousand, six hundred forty-four".