71351809 has 3 divisors (see below), whose sum is σ = 71360257. Its totient is φ = 71343362.

The previous prime is 71351789. The next prime is 71351837. The reversal of 71351809 is 90815317.

It is a happy number.

The square root of 71351809 is 8447.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90815317 = 419 ⋅216743.

It is not a de Polignac number, because 71351809 - 2¹⁵ = 71319041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71351899) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4224 + ... + 12670.

Almost surely, 2^71351809 is an apocalyptic number.

71351809 is the 8447-th square number.

71351809 is the 4224-th centered octagonal number.

It is an amenable number.

71351809 is a deficient number, since it is larger than the sum of its proper divisors (8448).

71351809 is an frugal number, since it uses more digits than its factorization.

71351809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16894 (or 8447 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 34.

The cubic root of 71351809 is about 414.7645812409.

The spelling of 71351809 in words is "seventy-one million, three hundred fifty-one thousand, eight hundred nine".