81256143 has 4 divisors (see below), whose sum is σ = 108341528. Its totient is φ = 54170760.

The previous prime is 81256099. The next prime is 81256151. The reversal of 81256143 is 34165218.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81256143 - 2¹² = 81252047 is a prime.

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

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81256143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81256183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13542688 + ... + 13542693.

It is an arithmetic number, because the mean of its divisors is an integer number (27085382).

Almost surely, 2^81256143 is an apocalyptic number.

81256143 is a deficient number, since it is larger than the sum of its proper divisors (27085385).

81256143 is a wasteful number, since it uses less digits than its factorization.

81256143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27085384.

The product of its digits is 5760, while the sum is 30.

The square root of 81256143 is about 9014.2189345500. The cubic root of 81256143 is about 433.1304678965.

The spelling of 81256143 in words is "eighty-one million, two hundred fifty-six thousand, one hundred forty-three".