81438143 has 16 divisors (see below), whose sum is σ = 88231680. Its totient is φ = 74889216.

The previous prime is 81438127. The next prime is 81438179. The reversal of 81438143 is 34183418.

It is not a de Polignac number, because 81438143 - 2⁴ = 81438127 is a prime.

It is a super-2 number, since 2×81438143² = 13264342270576898, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81438043) 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, 169778 + ... + 170256.

It is an arithmetic number, because the mean of its divisors is an integer number (5514480).

Almost surely, 2^81438143 is an apocalyptic number.

81438143 is a deficient number, since it is larger than the sum of its proper divisors (6793537).

81438143 is a wasteful number, since it uses less digits than its factorization.

81438143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706.

The product of its digits is 9216, while the sum is 32.

The square root of 81438143 is about 9024.3084499589. The cubic root of 81438143 is about 433.4536063912.

The spelling of 81438143 in words is "eighty-one million, four hundred thirty-eight thousand, one hundred forty-three".