71481521 has 4 divisors (see below), whose sum is σ = 73413492. Its totient is φ = 69549552.

The previous prime is 71481517. The next prime is 71481533. The reversal of 71481521 is 12518417.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12518417 = 23 ⋅544279.

It can be written as a sum of positive squares in 2 ways, for example, as 46730896 + 24750625 = 6836^2 + 4975^2 .

It is a cyclic number.

It is not a de Polignac number, because 71481521 - 2² = 71481517 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71481551) 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, 965930 + ... + 966003.

It is an arithmetic number, because the mean of its divisors is an integer number (18353373).

Almost surely, 2^71481521 is an apocalyptic number.

It is an amenable number.

71481521 is a deficient number, since it is larger than the sum of its proper divisors (1931971).

71481521 is a wasteful number, since it uses less digits than its factorization.

71481521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1931970.

The product of its digits is 2240, while the sum is 29.

The square root of 71481521 is about 8454.6745058577. The cubic root of 71481521 is about 415.0157655984.

Adding to 71481521 its reverse (12518417), we get a palindrome (83999938).

The spelling of 71481521 in words is "seventy-one million, four hundred eighty-one thousand, five hundred twenty-one".