81386481 has 16 divisors (see below), whose sum is σ = 124611840. Its totient is φ = 46728720.

The previous prime is 81386479. The next prime is 81386483. The reversal of 81386481 is 18468318.

It is an interprime number because it is at equal distance from previous prime (81386479) and next prime (81386483).

It is not a de Polignac number, because 81386481 - 2¹ = 81386479 is a prime.

It is a super-2 number, since 2×81386481² = 13247518579126722, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81386483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64275 + ... + 65528.

It is an arithmetic number, because the mean of its divisors is an integer number (7788240).

Almost surely, 2^81386481 is an apocalyptic number.

It is an amenable number.

81386481 is a deficient number, since it is larger than the sum of its proper divisors (43225359).

81386481 is a wasteful number, since it uses less digits than its factorization.

81386481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129836.

The product of its digits is 36864, while the sum is 39.

The square root of 81386481 is about 9021.4456158645. The cubic root of 81386481 is about 433.3619301969.

The spelling of 81386481 in words is "eighty-one million, three hundred eighty-six thousand, four hundred eighty-one".