71512421 has 4 divisors (see below), whose sum is σ = 75719052. Its totient is φ = 67305792.

The previous prime is 71512417. The next prime is 71512429. The reversal of 71512421 is 12421517.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21031396 + 50481025 = 4586^2 + 7105^2 .

It is a cyclic number.

It is not a de Polignac number, because 71512421 - 2² = 71512417 is a prime.

It is a super-2 number, since 2×71512421² = 10228052714562482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71512429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2103290 + ... + 2103323.

It is an arithmetic number, because the mean of its divisors is an integer number (18929763).

Almost surely, 2^71512421 is an apocalyptic number.

It is an amenable number.

71512421 is a deficient number, since it is larger than the sum of its proper divisors (4206631).

71512421 is a wasteful number, since it uses less digits than its factorization.

71512421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4206630.

The product of its digits is 560, while the sum is 23.

The square root of 71512421 is about 8456.5016998757. The cubic root of 71512421 is about 415.0755579269.

Adding to 71512421 its reverse (12421517), we get a palindrome (83933938).

The spelling of 71512421 in words is "seventy-one million, five hundred twelve thousand, four hundred twenty-one".