81062521 has 4 divisors (see below), whose sum is σ = 81123444. Its totient is φ = 81001600.

The previous prime is 81062497. The next prime is 81062539. The reversal of 81062521 is 12526018.

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 55711296 + 25351225 = 7464^2 + 5035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81062521 is a prime.

It is a super-2 number, since 2×81062521² = 13142264621750882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81062591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28420 + ... + 31141.

It is an arithmetic number, because the mean of its divisors is an integer number (20280861).

Almost surely, 2^81062521 is an apocalyptic number.

It is an amenable number.

81062521 is a deficient number, since it is larger than the sum of its proper divisors (60923).

81062521 is a wasteful number, since it uses less digits than its factorization.

81062521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60922.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 81062521 is about 9003.4727189013. The cubic root of 81062521 is about 432.7861645434.

Adding to 81062521 its reverse (12526018), we get a palindrome (93588539).

The spelling of 81062521 in words is "eighty-one million, sixty-two thousand, five hundred twenty-one".