81417231 has 20 divisors (see below), whose sum is σ = 138998992. Its totient is φ = 46523808.

The previous prime is 81417229. The next prime is 81417257. The reversal of 81417231 is 13271418.

It is not a de Polignac number, because 81417231 - 2¹ = 81417229 is a prime.

It is a super-2 number, since 2×81417231² = 13257531007414722, which contains 22 as substring.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81417195 and 81417204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81417331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 71230 + ... + 72363.

Almost surely, 2^81417231 is an apocalyptic number.

81417231 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81417231 is a deficient number, since it is larger than the sum of its proper divisors (57581761).

81417231 is a wasteful number, since it uses less digits than its factorization.

81417231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143612 (or 143603 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 81417231 is about 9023.1497272294. The cubic root of 81417231 is about 433.4165019196.

Adding to 81417231 its reverse (13271418), we get a palindrome (94688649).

The spelling of 81417231 in words is "eighty-one million, four hundred seventeen thousand, two hundred thirty-one".