81541239 has 32 divisors (see below), whose sum is σ = 119906304. Its totient is φ = 48988800.

The previous prime is 81541237. The next prime is 81541249. The reversal of 81541239 is 93214518.

It is not a de Polignac number, because 81541239 - 2¹ = 81541237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81541237) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 500172 + ... + 500334.

It is an arithmetic number, because the mean of its divisors is an integer number (3747072).

Almost surely, 2^81541239 is an apocalyptic number.

81541239 is a deficient number, since it is larger than the sum of its proper divisors (38365065).

81541239 is a wasteful number, since it uses less digits than its factorization.

81541239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407.

The product of its digits is 8640, while the sum is 33.

The square root of 81541239 is about 9030.0187707446. The cubic root of 81541239 is about 433.6364383641.

It can be divided in two parts, 81 and 541239, that added together give a triangular number (541320 = T₁₀₄₀).

The spelling of 81541239 in words is "eighty-one million, five hundred forty-one thousand, two hundred thirty-nine".