71561371 has 4 divisors (see below), whose sum is σ = 81784432. Its totient is φ = 61338312.

The previous prime is 71561363. The next prime is 71561377. The reversal of 71561371 is 17316517.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 71561371 - 2³ = 71561363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71561377) 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, 5111520 + ... + 5111533.

It is an arithmetic number, because the mean of its divisors is an integer number (20446108).

Almost surely, 2^71561371 is an apocalyptic number.

71561371 is a deficient number, since it is larger than the sum of its proper divisors (10223061).

71561371 is a wasteful number, since it uses less digits than its factorization.

71561371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10223060.

The product of its digits is 4410, while the sum is 31.

The square root of 71561371 is about 8459.3954275705. The cubic root of 71561371 is about 415.1702422450.

Adding to 71561371 its reverse (17316517), we get a palindrome (88877888).

The spelling of 71561371 in words is "seventy-one million, five hundred sixty-one thousand, three hundred seventy-one".