81859743 has 72 divisors (see below), whose sum is σ = 148852080. Its totient is φ = 43061760.

The previous prime is 81859711. The next prime is 81859753. The reversal of 81859743 is 34795818.

81859743 is a `hidden beast` number, since 8 + 18 + 597 + 43 = 666.

It is not a de Polignac number, because 81859743 - 2⁵ = 81859711 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81859753) 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 71 ways as a sum of consecutive naturals, for example, 457228 + ... + 457406.

It is an arithmetic number, because the mean of its divisors is an integer number (2067390).

Almost surely, 2^81859743 is an apocalyptic number.

81859743 is a deficient number, since it is larger than the sum of its proper divisors (66992337).

81859743 is a wasteful number, since it uses less digits than its factorization.

81859743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 267 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 81859743 is about 9047.6374264224. The cubic root of 81859743 is about 434.2003064273.

The spelling of 81859743 in words is "eighty-one million, eight hundred fifty-nine thousand, seven hundred forty-three".