71521718 has 4 divisors (see below), whose sum is σ = 107282580. Its totient is φ = 35760858.

The previous prime is 71521717. The next prime is 71521727. The reversal of 71521718 is 81712517.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81712517 = 29 ⋅2817673.

It is a super-2 number, since 2×71521718² = 10230712291343048, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71521717) 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 as a sum of consecutive naturals, namely, 17880428 + ... + 17880431.

It is an arithmetic number, because the mean of its divisors is an integer number (26820645).

Almost surely, 2^71521718 is an apocalyptic number.

71521718 is a deficient number, since it is larger than the sum of its proper divisors (35760862).

71521718 is a wasteful number, since it uses less digits than its factorization.

71521718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35760861.

The product of its digits is 3920, while the sum is 32.

The square root of 71521718 is about 8457.0513774010. The cubic root of 71521718 is about 415.0935445003.

The spelling of 71521718 in words is "seventy-one million, five hundred twenty-one thousand, seven hundred eighteen".