81242771 has 8 divisors (see below), whose sum is σ = 83663664. Its totient is φ = 78842880.

The previous prime is 81242767. The next prime is 81242773. The reversal of 81242771 is 17724218.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81242771 - 2² = 81242767 is a prime.

It is a super-3 number, since 3×81242771³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81242773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2780 + ... + 13046.

It is an arithmetic number, because the mean of its divisors is an integer number (10457958).

Almost surely, 2^81242771 is an apocalyptic number.

81242771 is a deficient number, since it is larger than the sum of its proper divisors (2420893).

81242771 is a wasteful number, since it uses less digits than its factorization.

81242771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10501.

The product of its digits is 6272, while the sum is 32.

The square root of 81242771 is about 9013.4771869684. The cubic root of 81242771 is about 433.1067070741.

Adding to 81242771 its reverse (17724218), we get a palindrome (98966989).

The spelling of 81242771 in words is "eighty-one million, two hundred forty-two thousand, seven hundred seventy-one".