71672809 has 4 divisors (see below), whose sum is σ = 77186116. Its totient is φ = 66159504.

The previous prime is 71672803. The next prime is 71672813. The reversal of 71672809 is 90827617.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90827617 = 17 ⋅5342801.

It can be written as a sum of positive squares in 2 ways, for example, as 39501225 + 32171584 = 6285^2 + 5672^2 .

It is a cyclic number.

It is not a de Polignac number, because 71672809 - 2¹¹ = 71670761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71672803) 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 3 ways as a sum of consecutive naturals, for example, 2756634 + ... + 2756659.

It is an arithmetic number, because the mean of its divisors is an integer number (19296529).

Almost surely, 2^71672809 is an apocalyptic number.

It is an amenable number.

71672809 is a deficient number, since it is larger than the sum of its proper divisors (5513307).

71672809 is a wasteful number, since it uses less digits than its factorization.

71672809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5513306.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 71672809 is about 8465.9795062355. The cubic root of 71672809 is about 415.3856366028.

The spelling of 71672809 in words is "seventy-one million, six hundred seventy-two thousand, eight hundred nine".