81242271 has 40 divisors (see below), whose sum is σ = 139392000. Its totient is φ = 46636560.

The previous prime is 81242251. The next prime is 81242299. The reversal of 81242271 is 17224218.

It is not a de Polignac number, because 81242271 - 2¹⁵ = 81209503 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81242251) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 14530 + ... + 19328.

It is an arithmetic number, because the mean of its divisors is an integer number (3484800).

Almost surely, 2^81242271 is an apocalyptic number.

81242271 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81242271 is a deficient number, since it is larger than the sum of its proper divisors (58149729).

81242271 is a wasteful number, since it uses less digits than its factorization.

81242271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4841 (or 4832 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 81242271 is about 9013.4494506820. The cubic root of 81242271 is about 433.1058185692.

Adding to 81242271 its reverse (17224218), we get a palindrome (98466489).

The spelling of 81242271 in words is "eighty-one million, two hundred forty-two thousand, two hundred seventy-one".