71943209 has 16 divisors (see below), whose sum is σ = 78968400. Its totient is φ = 65145600.

The previous prime is 71943197. The next prime is 71943247. The reversal of 71943209 is 90234917.

It can be written as a sum of positive squares in 8 ways, for example, as 912025 + 71031184 = 955^2 + 8428^2 .

It is not a de Polignac number, because 71943209 - 2⁸ = 71942953 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71942209) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205967 + ... + 206315.

It is an arithmetic number, because the mean of its divisors is an integer number (4935525).

Almost surely, 2^71943209 is an apocalyptic number.

It is an amenable number.

71943209 is a deficient number, since it is larger than the sum of its proper divisors (7025191).

71943209 is a wasteful number, since it uses less digits than its factorization.

71943209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 71943209 is about 8481.9342723226. The cubic root of 71943209 is about 415.9073561725.

The spelling of 71943209 in words is "seventy-one million, nine hundred forty-three thousand, two hundred nine".