81541139 has 8 divisors (see below), whose sum is σ = 82494960. Its totient is φ = 80591616.

The previous prime is 81541133. The next prime is 81541151. The reversal of 81541139 is 93114518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81541139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81541133) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50852 + ... + 52430.

It is an arithmetic number, because the mean of its divisors is an integer number (10311870).

Almost surely, 2^81541139 is an apocalyptic number.

81541139 is a deficient number, since it is larger than the sum of its proper divisors (953821).

81541139 is a wasteful number, since it uses less digits than its factorization.

81541139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2149.

The product of its digits is 4320, while the sum is 32.

The square root of 81541139 is about 9030.0132336559. The cubic root of 81541139 is about 433.6362610973.

The spelling of 81541139 in words is "eighty-one million, five hundred forty-one thousand, one hundred thirty-nine".